First we have to take the sidebar and make it a "relative" position. Use the following CSS code:
CSS Code (Relative Position)
Then we take the section (eg. the search bar) and give it a position of absolute.
CSS Code (Absolut Position)
top: 100px; /*adjust pixels to your liking*/
left: 100px; /*adjust pixels to your liking*/
With the z-index you stack your div's in a certain order. 1 being the lowest you can go and 9999 being the highest you can go.