Via the menu item Settings -> Room categories you can manage your room types or categories. A category is assigned to rooms and price categories.
All existing room categories are listed in the overview.
Click on Create room category to open the mask for creating a new room type.
If you click on the symbol you get the detail view.
When you click on the symbol in the overview under Actions you get the form for editing. Here you can edit all fields the same way as when you add an item.
If you click on the symbol under Actions in the overview, the selected element can be deleted.