@ruthmoses When transferring to the EA App, you'll need to redownload and reinstall all your Sims 3 Store content; otherwise it won't load properly in-game. Since you've already backed things up, the simplest procedure is to move the entire Sims 3 folder out of Documents > Electronic Arts and onto your desktop, launch the game to create a new folder, download fresh copies of your Store items, and install them in small batches.
Load a new save to make sure everything shows up, and if it does, you can move your saves, mods, Library files, etc. to the new Sims 3 folder and pick up where you left off. It's best to leave behind any files you don't need, for example cache files or even screenshots if you're willing to store them elsewhere.
Make sure not to transfer over any Store downloads in the Downloads folder, any files that end in .ebc inside DCCache (these are bundled store content, which you will have reinstalled), anything at all in DCBackup (the only important file is ccmerged, which you'll have recreated), or Store world files in InstalledWorlds. If you own any Store venues, you'll likely have duplicates in the old Library folder, and in that case, keep the new ones from your newly installed Store content and trash the old ones. They should have the same names and be exactly the same size.
Generally speaking, your expansion and stuff packs should all be available in the EA App, but please let me know it you're missing anything.
