Custom Content Not Showing in Sims 4

I recently downloaded a single item of custom content, and have repeatedly opened and closed the game, but it never appears. After I put the custom content in my mods folder, the game restarted, deleting all of my sims, households, custom content and progress, yet the hours I have played the game still remain. I have restarted my computer (A MacBook Air), made sure that my game allowed mods, checked for extra subfolders, and done just about everything that the internet recommends. Custom content has worked for me before, so I have no idea what's going on. Some insight into this issue would be much appreciated.

Thanks!