I've got a bunch of .gif files, one index.html file and one styles.css file. What do I do with them in terms of putting content in and uploading them to my site?
Number of methods, you can write a simple CMS script and use the index file as the main template, or you can apply the script to your favourite CMS script. I'm sorry, but the question you're asking is fairly broad.
Well, I have a template that I want to apply to my site somehow. I'll take a look at CMS scripts but could you tell me more about them?
Are you serious? Firstly, I would advise against CMS in your case, at least for the moment, given your obvious lack of knowledge on websites. You would tie yourself in a knot trying to figure a CMS out. "CMS," by the way, stands for "Content Management System". If you're out of your depth with a template, you haven't a hope in hell of getting to grips with CMS. Do you have an existing website that you are trying to upgrade or are you trying to get one off the ground from scratch?
A bit of both. I've managed to upload the template and I'm editing it at the moment. I'm not sure if I'm allowed to post a link for you to see what it is but when I've edited it, I'll swap the two main pages over and then work and getting the content into the template. What I did was create a folder for the test, upload the .css and html files to the /test directory and then created /test/images and uploaded the images and then just went to the page on my website and it worked