as the title said, I am interested to learn Dutch at the moment to communicate with someone I know in te fediverse.
but the question is, where I should start? Common place I would start with, of course is Duolingo. But is there some proper resource to learn?
I've been scrolling through anki cards but couldn't find the most suitable one. I am open to any book resources, but I hope it has the e-book version for me to purchase.
I think Duolingo is a great place to start learning. I recommend joining a course, which has helped me immeasurably more than Duolingo with learning Swedish. Interacting with a native speaker (or someone closer to that level) is a great way to develop the skill, as they will be able to pick up what you are struggling with. Getting engaged in some video content is also nice, but I guess what would be good for you greatly depends on your interests and current skill level.
There are plenty of resources that help new speakers. I think a great start would be to search for keywords like 'eenvoudige taal' (easy/simple language), 'nederlands voor kinderen' (Dutch for children), and the like. I think it's great learning language from stuff that is meant for (Dutch) children, like https://www.dutchforchildren.nl/gratis-nederlands-lesmateriaal/.
When you're at about A2-level (and live in NL) you might like to try something like this: https://iwcn.nl/work/my-local-friend/. It's an organization that connects native speakers with non-native speakers to hone the Dutch of the non-native speaker in a way that works best for them.
Dutch people will often switch to English as soon as you start struggling/they hear something out of place/etc., a nice trick to keep things in Dutch is by saying: "Ik spreek geen Engels" ("I don't speak English", who cares if it's a lie!)