First off, welcome to the obtuse and poorly documented world of Monster Hunter!
Yes, the gist of combat is to figure out the weak points and hit those weak points. There is more to combat (like breaking monster parts, severing tails, status effects, mounting, tripping, knockouts, elemental weaknesses, using the environment, traps) but it always comes back to whacking away at weak spots.
This all depends on the weapon you’re using. Each weapon has a variety of attacks, combos, etc. Which weapon are you using? I can give you the basics, but the training room can also help you out with this. The best resource is of course youtube. I would recommend Arekkz or Gaijinhunter’s youtube channels. They have great weapon tutorials.
The more “research” you do on any given monster the more information you unlock about the monster. Research involves gathering tracks, fighting the monster, and breaking monster parts. Look to the hunter’s notes often to learn about weaknesses/mechanics.
I wouldn’t worry much about this now, just go for the biggest attack value weapon you can make. Briefly, elemental damage is additional flat damage you get when using an elemental weapon type that a monster is weak to. You can see the type of elemental damage a weapon does in the weapon description.
At first, in town you just want to gobble up any missions you can find, make weapons/armor, eat meals, get bounties, and restock your item pouch from your box. Eventually other options open up, but don’t worry about those for now.