This place is big and it's normal to get a little bit lost when joining. Just to clear up some things:
Watchers are people who follow you. (like followers on Tumblr or subscribers on Youtube.)
You can watch other deviants as well, and when you watch someone you receive notifications about new work, journals, critiques they make etc etc
You can collect art by favoriting it!
You can also join Groups in dA. They are meant to bond users by a common interest and to give more exposure to deviant's works. You have many groups that are dedicated to everything art related, but some are only for a particular type of art, like traditional, or digital, or even writing. Just do a little search for what you want here.
Llamas are... well... they really don't have a purpose here X3 they're just fun and users like to collect them! You can give out as many llamas as you wish, but only one per deviant. You don't lose your own llamas when giving one to another person.
Daily Deviations are daily features chosen each day by a select group of volunteer members. Usually daily deviations are particularly impressive or otherwise interesting enough artworks that volunteers consider that deserve being brought to the attention of the community. You can check DDs here.
Points are dA's money. You can "buy" some deviations with points, but many people use real money to buy prints, or other kinds of things here on dA. You can also donate them to people with donations up.
Core members are users who paid (in points or money) for a special membership. By becoming core you can access to some things that aren't available for non core members. You can check those advantages here.
I hope this helps to clear up some questions! Enjoy your time here!