Ahaha, Sorry for replying late... (I got a little teary-eyed when i got home.)
So, The thing you just did with the drawing is just to show pictures. It doesn't really hold much significance. The chat thing...I don't actually know HOW it works.
Anyway, the basics.
Submitting Artwork: Basically you either post writings, W.I.Ps (Works in Progress) or completed artwork. It doesn't matter if it's not good quality or good artwork, you're putting it out there to see if others will like it so you can continue to aspire on being an artist/writer/ whatever else.
Comments: Comments are basically one way to communicate with another person, Chat groups are with LOTS of people. It's like how we skype eachother. Private messaging is called Notes, and they can be found on the top bar, the one with the mail icon. Hover over it and you'll see a link that has '0 Notes' on it. Click and you're in a private messaging thing.
Groups: Groups are basically founded by certain people and the founder title can be passed onto another person. Groups are made solely for other people to gather. Like those Cons we see on tumblr.
Watching: You basically watch people to be updated on when they submit an artwork/poll or journal and other things. Sometimes others watch you or unwatch you. That way, you're basically like gaining followers on tumblr. You can update frequently or non-frequently depending on how you want to run your account.
That's about all I know. Html codes aren't my forte so you might have to search that up.
Hope I help ya' Brooo~
((By the way, I can probably only contact you through Whatsapp so you better get'cho wifi quick when you get there.))