Welcome to Steemit salma1984. Let me know if you got any questions about Steem or anything related to it! The official FAQ can be found here and has A LOT of information https://steemit.com/faq.html - Also remember, Steemit is just ONE of the sites built that uses Steem the blockchain. We also have DTube - our very own Youtube, DSound for Soundcloud and Steepshot if you prefer Instagram like experience. I'd also like to mention ChainBB - forums, Busy - Steemit with more modern look basically, DMania for memes and Dlive for streaming just like in Twitch! Welcome to the blockchain