HTML - Need Assitance In A Web Bg

I want to make another website.. the last one i made. The host provided the Background(BG).. Now I want to make my own BG. Dont Know much about starting one! I can sure edit one, but dont know where to start..

Desciption:- I want to be able to place an image as the BG from time to time. With a Horizontal Navigation. I Want to be able to put a banner above the navigation. and i also want 2 sub-navigations, 1 on the left.. and the other on the right. i want to put all content in the middle.


I know im askin for alot .. Im still learning html my self ... Thanks in advance!!!..