Hello and welcome to deviantart! Since you already begun posting art, it's useless to explain you how it works here XD but let me spend a few words anyway.
I wish you the best stay here with us. Being an art community, here you have the possibility to find friends, inspiration, tutorial and much more! Comparison with other artists is the best way to develop our artistic skills and pushes us to get better and better everyday! I hope you will find in this community what you need to become the artist you want to!
Joining groups, making friends and joining contest, are only some of the ways you can interact with all the others! If you have question, problems...don't hesitate to contact me and I'll try to help as much as I can!