From the AppGallery home page:
1. On the menu bar, click Collections.
2. Click on the Collection from which you want to remove an app.
3. Click the 3 vertical dots on the tile of the app you would like to delete
4. Click Remove from collection. Doing so will immediately remove the app from your collection
Note: Removing an app from a Collection does not delete the app from your profile. To remove an app from your profile, you must delete it from the Apps screen.