Expansion packs Install?

I'm really stuck on how to INSTALL expansion packs? I can install the
game just fine, then I download the expansion packs I want right? It
confusing me because it says don't add the crack, then add a different
crack or update it then add crack I'm just confused, could you shed some
light on what to actually do after I install the base game please.

Okay, so you have The Sims 3 based installed, the expansions you want downloads, and extracted? After that you go to the folder of the expansion, nearish the bottom is Sims3 (EP/SP) (01-07) setup.exe, World Adventure's for example Sims3EP01Setup.exe, So it's a Expansion Pack, and 01, so the first one.

So you click on the file, and it will startup installing go forward with it till it ask you the serial code, go back to the folder with the setup file, and open #Installation Guide.txt on it, maybe have to scroll down a little you'll see a step about Serial Codes, so copy one of those, and paste it into your game's installer window, then just following it through to finish.

Repeat above for each expansion.

There is no need to apply cracks until your finish then you only need to patch/update to the latest version (1.39 at this time), and download the Ultimate fix for the latest version (1.39 at this time.) Then you'll apply the apply the Ultimate fix, and you should be ready to play.