how to add a in page menu (not the top navigation bar ) for mobile page?

I use the wptouch with my custom theme and it works pretty OK except I have a question on how to add a nav inside the page (the top right menu works perfect so not worry about that )? I google alots but didn’t see any solution. I think it’s hard to explain in word , what I want is make it like the amazon mobile ver , the bottom nav bar. Any suggest?