The Career Agent questlines are a good place to start and to get a feel for different aspects of the game. There's a lot of new player friendly corps who will show you the ropes, as well.
The game used to be way more confusing before they added things like The Agency - you can find lots of stuff to do through that.
You will probably be hard pressed to find someone who can teach you
everything. Most of your learning will either come from your own experience or research.
https://wiki.eveuniversity.org/ has lots of good info.
The main trade hubs are:
1. Jita IV - Moon 4 - Caldari Navy Assembly Plant
2. Amarr VIII (Oris) - Emperor Family Academy
3. Rens VI - Moon 8 - Brutor Tribe Treasury
4. Dodixie IX - Moon 20 - Federation Navy Assembly Plant
You'll get the best bang for your buck when buying ships/modules in those systems, but beware of scammers advertising in Local chat. Good luck and have fun. o7