Oh don't worry, I've read questions much worse
Basically you go to the group's main page and in the blue/purple bar above the "featured" widget should be "submit art", and then you choose your work. A sign should come up saying "Your submission is being reviewed" or something similar to that. And then your work shows up in my messages, I check them and then I either accept them or decline them. Don't worry too much, I'm not very strict about submissions.