bdbrown on "Trying to set up a site"

While I'm not too bad with HTML and PHP, my CSS knowledge is not as great as I'd like and I'm still getting used to WordPress coding. I tried downloading some layouts similar to what I had in mind to examine them to figure out how the coding works, but I'm still having issues.

More or less, I'm trying to have a rather simple layout like so (not in these colors of course--just to make each part more noticeable). It mostly just has a fixed background running through it, everything scrolls in this box, I figured it'd be simple enough to try and get a hang of what I need to put where, but instead, I have a large space between where the content should be (It's essentially acting like Navigation -> Header -> Body -> Footer instead of Header with Navigation -> Body -> Footer) and the footer where the content actually is.

I've tried so many things, but I can't seem to compact the layout correctly for how pages should work. I have one section where I want all the Blog Posts to be which will be the only part of the side with a widget sidebar so I need to play around with that as well, but I'm hoping once I can figure out the main layout, that part will be easy.

Does anyone have any idea what could be going wrong/what I should be looking for? None of it is saved/public so I can't properly link it, unfortunately. But I'm this close to just scraping everything and trying to re-do it all from scratch again :(