What am I supposed to be doing?

I get that the title is very broad but just bare with me for a second. I got the game a little over a week ago, and I'm thoroughly enjoying it. My only issue is that it's a little overwhelming. There's a tonne of stuff to do, and not much guidance or explanation for what things are past the base intro to the game. I am currently in a position where I have 2 purple champs, about a dozen rares and green/white champs overflowing. So basically...what do I do with it all? Are there certain champs I should be looking out for and focusing on? Should I join a clan? Which artifact sets are good and which ones are bad? Should I be worrying about the rarity of my artifacts this early in the game? Basically any info you feel you've got that might help a noob is massively appreciated. Also sorry for the wall of text, I'm on mobile and the formatting is weird when I separate lines.