I'm making my site with div layers, and I can't figure out to make it so that, no matter what size computer someone has, when they go to my site, it will fill up the whole screen, not just mine and then it be too small for someone elses, how do I accomplish this? (please write in easy words im naive lol) :lolol:

Instead of using width: 300px; use percentages instead, eg width: 30%;. The only problem you might run into is with header images, since they tend to look funny when resized.