Hi inevitabley, welcome to Tapas!. Don`t worry, you are figuring out stuff.
There are topics that encourage self-promotion. Those are the places to promote your comic/novel. (as long as you don`t put a thousand ads/links)
Some basic rules are:
1- don`t go off topic (for example this topic allows to talk about random stuff, but is not a place to promote your comic)
2-don`t be a jerk.
Also, if you create a topic make sure you put it in the right category or at least the one that fits the most.
Hope you enjoy your stay in the forums!