Submenu in side bar on mainpage?

Hopefully someone will be able to help me out with this:
I am making a website for a friend. I am using a childtheme of willingness.
There are two pages in the menu (Main menu) which have 7 or 8 subpages. Now I want these subpages in a list on the main page where they belong to. So in the left sidebar a list of the submenu pages related to that specific page.
I also want to be able to post on every page in the left and right widget areas phrases, quotes, links and pictures but I want to be able to make it different on any page?
Can someone please help me out?
And if it’s not possible with this theme does anyone knows a theme which should do this trick?