Prepare aluminum tubes (part no. 00008)
If you received the aluminum tubes with plastic motor mounts already attached - continue to the next point.
If you 3d-printed plastic parts on your own, you'll need to glue the plastic motor mounts to the tubes using an epoxy glue
Do not use cyanoacrylate glues - the 5 minute ones etc., because they tend not to stick to the plastic.
Ball bearings and sealing
Your kit may include 2x metal-covered bearings (no rubber-sealed bearing - black) - don't worry then, we're just experimenting with different types of bearings and all of them are just fine.
The same with rubber sealings - they may be different colour, don't worry as well.