To build your bunker exactly the way you want it, you don’t just need to decide on the layout of your Fallout Shelter. You can also decide on the aesthetics of some of the rooms. It may take time, but you can come up with “Themes” that you can apply to your dining rooms and living rooms to make them more interesting.

Themes allow you to show your allegiance to one or more factions of the Fallout franchise. You can also choose to visually separate your vault by using different themes as you expand your bunker.

To obtain themes in Fallout Shelter, you must complete two steps: find all nine theme recipe fragments, and craft the theme in the Theme Workshop. Each theme is divided into nine theme recipe fragments that can be found throughout the Wasteland while completing Overseer's Office quests and later crafted in the Theme Workshop.

To start, you'll need to build the Overseer's Office to unlock quests, and to do so, you'll need to have at least 18 dwellers in your Vault and spend 1000 Caps to build it. You'll need to complete multi-stage quests like Climbing the Ranks, Almost Human, and Food Glowrious Food to collect the themed recipe fragments.