The dungeon spawn pools screen is used to configure pools. A pool is a list of races that can then be applied to a room instead of having one specific race spawn.
It can be kind of interesting to have multiple races spawn in a dungeon room as it makes the dungeon more diverse.
Adding a new pool
You can use the button at the bottom of the screen to add a new dungeon pool.
Renaming a pool
Select the pool then enter a new name on the right of the screen and click the save button.
Deleting a pool
Select the pool then click the delete button.
Configuring the pool race list
Select the pool then click the configure button on the right of the screen.
Use the configure screen to select and then add new races to the pool or to select and then remove races that are currently on the pool list.
When you are done use the Back button to go back to the previous screen.
You can use the Pool button at the bottom of the main spawn screen to switch to pool mode to set a room to use your pool list.