I have Sims 3 on Steam. I want to play Roaring Heights how do I download it?

@slothincloud24  First, make sure your CD key for the base game is registered to your EA account.  You can add it on www.thesims3.com rather than using the EA App, and in fact that's worth doing just to confirm that you have an active account on that website.

Rather than using the EA App, buy Roaring Heights from the website:

https://www.ea.com/games/the-sims/the-sims-3/the-sims-3-roaring-heights/buy-microcontent

You'll receive a confirmation email with a product code included.  Register that code on the same Sims 3 site, and download it from there, either from your purchase history (Store > My Store Account > Purchase History) or from its product page.

https://store.thesims3.com/roaringheights.html?categoryId=12642

You don't need to use the EA App at all, and the product code won't work in Steam.  Store worlds can only be installed through the Store site.

For more information about registering and installing Store worlds, please see the first post of this thread:

https://answers.ea.com/t5/Store-Issues/Sims-3-Store-world-can-t-register-install/td-p/12619800

I am in a similar predicament, owning sims 3 (all nearly all dlc) on steam instead of ea (although I do have the base game only on there from transferring the code some years ago). However, when buying the world, I had no choice but to buy it on the ea app, and I attempted to follow the method of redeeming a code on the sims 3 store site (which is linked to the same sims 3 account), but that did nothing. Is there anything else I could do to get it working, given I just spent £7.50 on roaring heights, and it would be annoying to see that money down the drain basically. 

Sims 3 store is not redeeming world codes right now. Some kind of error they have finally admitted is on their side.  Lots of people not able to redeem codes in the store so you are far from alone.  They say they will fix it but so far nothing. You might go to EA help. Good luck I am still waiting for them to fix. I do not want a refund I want the world I bought.

EA help is at the bottom of this forums page by the way.  Watch out for getting timed out it takes forever for them to answer some times. Good luck again.

MrCow979​  Here's the master thread for the issue redeeming Store world codes:

Issue redeeming Sims 3 World codes | EA Forums - 13032508

Having said that, you can absolutely buy worlds from the EA website, for example:

https://www.ea.com/en/games/the-sims/the-sims-3/buy/addon/the-sims-3-roaring-heights

Google "buy [world name]" if you can't find the link to another world by searching that site.

And my original point still stands: you can download your Store content into a Steam install without involving the EA App at all.  I do it all the time when I refresh my user folder.