How do I start composting?

I just read your post more carefully. Obviously you have a lawn. Composting can be very simple or very complicated, depending on what you want. Sounds like you want simple for now.

If you want a simple setup you basically need two things:

A container that will loosely hold your compost and some stuff to rot.

First the container. There are lots of commercial options but really, any sort of decently tall box-like structure will do. Many make them out of old pallets. Super simple and cheap if you can find them.

Next is the stuff you put in it. For an easy compost situation, you just need to keep some things in mind.

1. Avoid meat. Your compost will not get hot enough for this in all likelyhood.
2. Avoid anything with seeds if you plan on using your soil for gardens. Again, it probably wont get hot enough to kill them and they will grow in your garden.
3. Lots of brown stuff! Think leaves. More leaves. And even more leaves. This will bulk your compost up.
4. Careful with weeds. Its tempting to throw weeds in the compost but again, if you are using it for gardens it might end up just growing a crapload of weeds.
5. Add some green matter. Think salad leaves, stems, etc. The only thing to worry about here is to be careful not to throw anything in you think will attract a ton of animals.

And thats pretty much the basics. You can turn it from time to time but you dont HAVE to. If you live somewhere dry you might want to water it from time to time too but if you get rain it should be fine.

Remember, at its simplest youre piling stuff up to rot. Nature does the rest. You can get into the nitty gritty later. For now, just start and experiment.

Cheapest and messiest: pile on the ground.

Cheap and contained: pallets or chicken wire.

Expensive but easy and not ugly: a kit like this https://greenesfence.com/collections/cedar-composter

Skip the tumblers unless you're really not ready to commit to a location in your yard. I ended up giving mine away a year into it.

garden composting and vermicomposting and hot composting and chicken tractors and compost tea can all be somewhat different disciplines – as well as the scale you are working at (apartment balcony garden all the way up to an agroforestry acreage)

• plain garden composting is usually easiest with a basic 3 bay setup – garden trimmings and prunings get piled into the first bay, as it breaks down, it’s flipped over into the second bay to continue the process, then finished in the third bay where you pull from for adding back into your garden – add in regular watering to prevent the “pile of dry grass and twigs” – adjust the size of the bays to your needs, can be as simple as 3 garbage cans all the way up to a huge structure made from wood shipping palettes
• worm farm (vermicomposting) is generally the simplest use for kitchen scraps – Geoff Lawton has a good video – supposedly there are apartment worm farm kits that don’t smell but I would still keep them out on the balcony
• I even stumbled across a page from a balcony container garden in India where he sunk a large diameter PVC pipe into his containers and dumped kitchen scraps down the tube, as it composted, it filtered out into the bottom of the container

I don't bother composting grass. I usually just use it as mulch for my trees.

I try to mix it with dry leaves or shredded wood when I can to balance nitrogen or carbon.

As much as possible I prefer to compost in situ.

a little addendum on the lawn side of things

for a greener, healthier lawn

• mix in some clover (alsike, Trifolium hybridum) (especially inoculated clover seed if you can find it) into the lawn (nitrogen fixer, inoculated option adds in the right bacteria ahead of time)
  • also means avoiding any herbicides (but that’s just good practice anyways)
  • even better, add in both clover and dandelion (and a reminder that every part of a dandelion is edible)
• leave the lawn clippings in place as mulch (or shell out for a mulching lawn mower)
  • by removing the clippings, you’re removing nutrients from the system

EDIT:

• a lot harder to do with a mower, but if you don’t cut shorter than 6 inches (15cm) then you trigger the grass’s grazing response rather than the damage response

Read the book "The Humanure Handbook" by Joseph Jenkins. It's the best book written about composting in general and humanure in particular. It's available free from his website. I got it from the library and liked it so much I bought it and have read it 4 or 5 times. Here's what building a basic compost bin entails.

https://humanurehandbook.com

Build a compost bin with metal fencing similar to chicken wire, or other materials. The bin must be AT LEAST 1 cubic meter in size - mass is important. Bigger is better, though increasing the height above 1 meter makes it harder to manage and sqeezes oxygen from the pile. I like piles that are 1 meter high, 1 meter deep, and multiple meters wide. For your first real bin I'd suggest 1m3.

Add a minimum of half a meter deep of sponge material like dead plants to the bottom of the bin to keep certain contents like manure etc. from contacting the soil. A deeper sponger material is better and it will all turn into compost. To add material, form a depression in the center of the pile and add your food scraps (including meat, egg shells, old bread, fruit/veggie scraps, etc.) in the center. Add any other things as well at this time such as compost toilet material, used kleenexes, yard scraps, plain brown cardboard with tape removed, etc. Then cover this with a cover material such as hay (best) or dry leaves or other plant scraps. The cover material keeps flies away and prevents odors. You should be able to stand next to it with visitors and not smell anything.

Some people say not to add a huge number of things to compost like meat, milk, etc. and that's because they're not composting - they're doing something else that can't handle these inputs and wrongly calling it composting. Vermiculture for example is a different process (worm digestion) that results in a different product (worm castings, aka worm poop) that sells for a very different price. You can compost all these things and more, including large animals like bears and horses.

You don't need to (and shouldn't!) turn a compost pile. Doing so releases a ton of microorganisms into the air that you'll breathe in; it releases a ton of heat for no good reason; it loses moisture; and doing so is 90% of the work and is unnecessary to create compost. Work smart and let microorganisms (especially thermophilic bacteria) do the work for you.

Buy a compost thermometer (roughly half a meter long) and keep it in the middle of the pile 24/7. The high temperature of compost destroys seeds and kills pathogens. General rule of thumb: 60C for an hour kills pathogens, 55C for a day, or 49C for a week. Of course a properly managed biologically active compost pile will easily reach over 55C and stay there for days. The highest I've seen is 67C, which it held for a day or two. Hitting those high temperatures means your pile has sufficient mass with a nice balance of carbon and nitrogen and is moist, not soggy or dry.

General questions:

Where are you and what's your general environment like? Mostly urban? Suburban development with heavily-fertilized lawns? Gardening? Cook a lot of veggies?

What are you trying to do with compost? Feed a garden? Reduce landfill usage?

What to put in the compost:

Plain grass clippings are great but they don't usually compost all that well by themselves. The standard advice is to mix both "greens" (nitrogen-rich: grass, twigs, paper, corn husks, etc.) and "browns" (carbon-rich: leaves, vegetable & fruit scraps, animal manure) to get composting going.

Kitchen scraps are a great source of "browns" — peels, stems, coffee grounds, tea bags, etc. Pretty much anything from a vegetable source that doesn't have fertile seeds in it, is a good input to basic composting.

(Why do I call out fertile seed? If you throw a whole rotten tomato in the compost, you will get little tomato plants growing in there. Onion & carrot tops can also decide to grow in there, but they give up if you smash them a bit.)

Regarding earthworms:

The kind of earthworms that like to eat compost are not going to just spontaneously show up out of the ground, because the ground is mostly not compost. You can get them from someone else's compost; or they're also commercially available as "red wigglers" or compost worms.

Worm-based composting works pretty differently from straight composting. Some say that "vermicomposting" should really be called "vermidigestion" — it's relying on the digestive tract of the worm, not composting microbes, to break down your veggie garbage.