Bought my first gun ever immediately after the November election. When anyone brings up the stock market these days I tell them I'm investing in seeds, fresh water, and ammunition.
The 'under no pretext' phrase is significantly stronger than 'the right to bear arms' if both were the word of law. It explicitly says to confront anyone who threatens it.
Join a club or find some locals to tag along with. Go to a range and start shooting. I do suggest to start with a 22lr because of the cost of ammo these days, don't not practice with the larger calibers, but for $25 you can get 350+ rounds of 22lr vs like 40ish rounds of .223/556 or even less with 308.
Plinkers are so much fun. Great to practice with, no recoil, and not very loud. I suggest people have a .22 and a shotgun (for defense and to get a feeling for how to deal with recoil and sound without flinching). 20g can be affordable, too. 12g gets a little costly and can be a little too rough for those not prepared for them.
Point open end towards the thing you're shooting, press stock into armpit. Insert loaded magazine, pull back bolt, turn off safety, squeeze trigger. If automatic, squeeze trigger again, repeat. You can also find indoor ranges that will have classes usually. Most will have limits on calibers allowed though. Outdoor ranges usually have no limits (or do but aren't monitored).