multi page forms and genral form question

[eluser]The Casual Bot[/eluser]
I'm brand new to CI this is my first time working with a framework as normal i work in just PHP

So first was gutted about how much time i wasted in the last 2 year using PHP alone mirk:

Iv been asked to crate i form set to take personal details over about 8 pages there current ones pass the post data into hidden forms but it this does have problems as when the back button is used the data gets lost and the user sends a half full application.

iv done something similar before using just PHP and the session variables so even when the user pressed the back button it did lose and data

so to my question has anyone got any ideas on how best to code a multi page form and the logic they used (or would use) that would also display the data in the fields when the back button is used ???

and question 2 iv looked in the user guide but can find my answer to this iv turned on xss clean globally do i use the post values form my form or are they stored some where else

Thanks In Advanced :-)