@svr79 Okay, open Origin, click on My Game Library, then the Sims 4 icon, then Kits (it might be hidden behind More, and you might need to scroll down a little first), and scroll to Desert Luxe. Do you see a Download button or one that says Details? If you see a Download button, just click it.
If the pack is already downloaded, please clear Origin's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
and repair the game: open your game library again, right-click on the Sims 4 icon, and select Repair.