There are STL files available for download for interior trays.
These trays mount from standoffs inside the Fuselage body. All three trays have the same mounting hole spacing – so they can be mounted in any order together using standoffs.
The smallest tray is typically used for mounting a flight controller – and it is referred to as the “Flight Controller Tray.”
The two larger trays are typically used for mounting electronic equipment – and they are referred to as “Equipment Trays.”
Here a Holybro Pixhawk 6C Mini is sitting on the Flight Controller tray. Underneath is the ESC.
Here a CubePilot Cube and Mini Carrier Board is on the Flight Controller Tray.
Here nylon standoffs are used to secure the Flight Controller Tray and allow mounting an Equipment tray.
Here the Large Equipment Tray is mounted over the flight controller on the Flight Controller Tray.
Here nylon standoffs secure the Large Equipment Tray to allow for mounting a second Equipment Tray.
Here a Small Equipment Tray is mounted over both the Flight Controller tray and the Large Equipment Tray.
Here’s an example of a CubePilot Cube and Mini Carrier Board mounted on a Large Equipment Tray.
Here is an example of electronics mounted to the Small Equipment Tray, over other electronics below on the Large Equipment Tray.