MAKE SURE TO CHECK THE FILE TYPE. THE BELOW INSTRUCTIONS ARE FOR
.zip FILES ONLY
When you click download, an option should pop up that asks whether you want to save or open the file. Chose the option to open it, and if it's a zip file, winzip should come up. I don't have the full version of winzip, so it says something like "agree" or "evaluation version", so click whatever applies. After this the actual winzip window comes up, there will be an option to "extract" it. From this point just follow the instructions from the previous post.
If it's another filetype or it still doesn't work, post the problem specifically, and post the link to the mod so that I can try downloading it to see if it has any problems
Downloading mods can be annoying, but after a couple of times, you'll get it.