This will open a new window. From here, you can search for a specific part in the Search Custom Items field or scroll the list of previously-created items. You can sort the parts list alphabetically or by how recently they have been created.
Once you select your item(s) you'd like to add to the room, the Add Selected Items button will appear active.
Adding New Custom Items
If you don't see the item you need, you can select + Create New
This will open a new window where you can add the details of your new part. Once you enter information for all of the fields, the Create Custom Item button will become active. Once you select that, the part will be added to your Custom Items list.
NOTE: By popular vote, we've added the ability to edit already existing Custom Items. This includes moving them around and mixing them anywhere in the rooms!