1. Click the "Add Location" icon next to the category
To organize items under a category, first you'll need to add locations or rooms under that category to place them in. Not all categories will be relevant to every room in the project, so this lets you decide which ones to include. In this case, Appliances exist in the Kitchen.
2. Click on the room you want to add
You'll see a menu of locations or rooms for this project appear. Select the room you want to add. In this case we'll click "Kitchen"
3. The location will now be available to add things to
You'll now see "Kitchen" listed as a bucket underneath Appliances. You can now add items directly to it, or move items into it.