I couldn't get the premade folder to download on any browser I tried, but I was able to download the config file, I created a mods folder within documents, sims 3. I made sure they were packages and for the correct game (not sims 4 or something else) and it's still not showing up in the launcher. Does something here look wrong? (hopefully the images uploaded, not really sure how to use this forum)

Mods and store content are two separate things. The launcher in sims 3 only shows the installed store content, not mods. Mods that you put in your Mods folder won’t show up in the launcher, but they work in the game. Nothing is wrong with what you did - it’s just that the launcher doesn’t display mods, that has been installed in the Mods folder.