i need ur guidens to create websitebuilder. It look likes

first i have a button like "create your own pages."

when user clicks on this link you should get different opton like

> menu bar creation
> style sheet upload for that site
> new page creation etc.

different users may create different pages with diferent styles.

if a user is logged in his own style of pages should display.

How experienced are you in php? mysql or other database? ajax?
How much time can you dedicate?
How will everything be stored? as templates? in db?
How will it handle forms? images? stylesheet? vidoes? and more stuff?
This wont be a quick job, (especially if you want to do it right) it will take a lot of time and will have need for dedication, and at least medium knowledge of everything used.
Basically from your question I think you need to start of with something smaller?

Ya, I would suggest that you go and mess up a couple times on some smaller items before taking this on, and be prepared for a lot of frustration and patients.