I’m not sure I understand your question, but I think that if you do two things, you might get an idea of how to do what you want.
First, go to Tools | Configuration | Site Start and set the site start to the ID of the page you want as your home page (the IDs are in parentheses next to the names in the document tree at the left).
Next, put a Wayfinder call in your template (if there isn’t one there already).
[[Wayfinder? &startId=`0`]]
Instead of 0 you might want to set startId to the site start page.
Wayfinder will present a menu based on the document tree and when you move things around in the tree (which you can do by clicking on the little folder image and setting their parent), they will automatically move in the menu. Newly created documents will also show automatically in the menu if they are published and set to show in menus.
Hope this helps.