Can someone please explain Roleplay sites to me?

Basically what toi do in a roleplay is toi create ou claim a character and toi portray him/her. toi 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 toi :)
www.supernaturalroleplay.piczo.com
yeah i checked out the site toi signed up for and it seemed pretty confusing..
but mine is a LOT simpler to follow in case you're wondering :)