It's not an overly difficult print, but needs a ton of support material. I cut down quite a bit of the supports by cutting the front off, making H10 Spare Mount Spacer. I've printed them with traditional supports and tree mode, and neither looks any better, but the normal supports came off pretty easy, while tools were needed to remove the trees, because of how the supports were grown around the tubes. Note the horrible quality of the prototype. Please buy all my designs several times so I can join the future with a Bambu Labs printer :P

The only hardware needed are:
2 - M3x6 to M3x15 button head screws to join the spacer to the mount. Longer screws reinforce the front of the mount.
1- M4x10-ish button head screw. This is to attach the spare. Whatever length is enough to go through the wheel and mount.

It's best to screw the mount to the spacer, then put the rear tab in place, and rotate the mount forward and down, making sure the chassis crossmember's bosses go into the bottom of the spacer. The two original screws into the front from the bottom, two into the rear from the top.