Get alone boomer and just let it swing at you a while - they do very little damage, don’t bite (which causes infection - almost all other zombies do that), and don’t cause bleeding (which several other zombies do, especially skeletons). It’s a great way to get your dodge up… I think it caps at 4 against Boomers (you have to find better fighters to dodge after that).
Fabrication is your friend! It lets you make stuff. Hit & - you have to have enough light (top right corner in the & menu tells you the brightness). Make stuff that’s the highest level you can make to train fabrication so you can make better stuff.
Tailoring is also your friend! It lets you repair your clothes, fit your clothes (so they cause less encumbrance) and eventually make good clothes/armor. All you need is a needle (which you can make with fabrication skill level 0) and thread (which you can get by disassembling rags - rags you can get by Butchering any clothes you don’t want. Well, you’ll also need rags sometimes, depending on how badly damaged your clothing is.
Construction can be helpful - hit *. Train it the same way you train fabrication (make the best stuff you can). You can use it to build walls if you get it high enough, and you can build line-of-sight blocking furniture earlier than that (all zombies can bash that down, but only if they want to go through there… which they probably won’t if they can’t see you!).
Get a pot or a frying pan ASAP so you can boil water (to get clean water) and cook meat (eating raw meat can be bad for you). Both of those will train your cooking skill some… and, at least for the early game, that’s all you need cooking for, and you can do it at cooking skill 0.
Look for books - some of them will train your skills if you read them or teach you recipes (under look in the fabrication menu). You don’t have to learn the recipes if you have the book nearby.
If you don’t have a bed, roll mat, cot, or couch to sleep on, make a pile of clothes you don’t want/need and sleep on that - it’s quite a bit better than nothing.
That’s the basics.