This is a 'vane' style air pump/vacuum. The internal core spins inside an offset chamber. The core acts like a centrifuge and tosses its vanes outward. The vanes hit the wall of the chamber, trapping air that flowed in from the intake hole. As the core rotates, the offset of the chamber pushes the vanes back inwards, forcing the air out the escape hole.  This type of pump must be printed in a high-temperature material such as nylon or carbon-fiber otherwise the generated heat will fuse the vanes to the inside walls.  I found this out the hard way.

A hobby motor is meant to attach to the base of the pump by means of a couple M3 machine screws.  The core is friction fit onto the motor shaft. The vanes float freely and the whole system is closed by sandwiching the lid and base together via nuts and some M4 machine screws. You can also add some 1/8"NPT Push-Fit hose connectors to the input-output ports such as I have.