CSS 3 Layout Fixes Help Please

After much editing I am setting on a more usable experience. So there are two items of immedite attention and a third which I can explore on my own.

This site is a single scroll. Landing on the homepage and then scrolling down to a fixed header which the rest of the content goes under. These navigation links target each section of the scroll.

1> How to I make the landing page section visible only and not the other section or page in the browser viewable area?

2> When scrolling down how do I display the header to scroll and fix itself to the top of the first section and the rest of the sections will continue to scroll under the fixed header?