Can someone please explain Roleplay sites to me?

Basically what u do in a roleplay is u create of claim a character and u portray him/her. u have conversations with other characters, etc. At least that's how most roleplays go...
i recently just started my own supernatural roleplay if you're interested in joining, we'd be happy to have u :)
www.supernaturalroleplay.piczo.com
yeah i checked out the site u signed up for and it seemed pretty confusing..
but mine is a LOT simpler to follow in case you're wondering :)