Sims 3 University not working

Help please! I have downloaded the Sims 3 base game and sims university life and i have followed the instructions giiven but whenever i try and play it a text pops up saying it's invalid and i need to add a code.

Hi there, @dizziilizzii, and welcome to the Games4theworld Forum!

Did you also follow the instructions of this guide?
https://games4theworld.forumotion.com/t1171-must-read-how-to-install-the-sims-3-correctly

If you didn't, then it's very important that you do. Follow the Steps 2, 4 and 5 and let us know how it goes. Good luck!