Moving Sims 4 onto an external hard drive

I recently updated my game after the recent Love Struck update - previously, everything was working fine. 

Once updated, I launched the sims 4 app and everything was fine. I still had my saves and all I had to do was enable my mods and scripts again. I done this and restarted my game, however my app failed to launch. I therefore removed my mods folder and deleted the cache folder on my EA app. When I relaunched the game, everything was gone as if I had just started the game for the very first time. 

As I use an external hard drive (Seagate to be specific) - I figured that I had to go back and make sure that the installation location was correct. It had originated back to my documents folder rather than my external hard drive. I have since changed this via the EA app, however when I launch the game, I still have nothing. In my external hard drive, I still have all of my original folders (EA folder, sims 4, mods, saves, etc). How do I launch my game so that I still have everything? I think that I understand that I need to create a symbolic link - am I on the right track?