I build this house in Sims 4 to test if I can upload it here. If it's working Marbi can upload her fabulous lots to Affinity
I only have the base game and didn't use any CC.
To get the lot in your game, you have to go to Documents / Electronic Arts / The Sims 4 / Tray
Extract and copy All the files
Open the Tray folder and paste ALL the files into the Tray folder.
Now this lot should be in your Library.