Objects have been optimised for best results on my Up! 3D printers. Supports are necessary, and some sanding may be required to make everything fit and spin properly.
The Pokestop has two base choices: a regular upright position like in the game, or an L shaped base for attaching the Pokestop to walls and posts. Assembling this is as simple as fitting the round peg into the round hole, the rectangle-round peg into the the corresponding hole, and plugging the base into the bottom of the Pokestop body.
The parts have been designed with a very small tolerance to reduce the need for glue, but some work will be required based on the quality of print.
The central Pokestop is pinned together with a piece of 1.75 mm filament. Thread the filament through the hole in the top, passing it through the central disk and the space part, ensuring that the spacer is on the bottom. The filament will notch back into the larger body, holding everything in place.
You may have to repeat this several times over as you test how well everything spins.
My 3D printing software did not like how small the Spacer part was, so a modified version (Spacer_B) was made that appeared larger.
I encountered issues when printing the Spacer part by itself. The small object deforms if the layers are not given enough time to cool between depositions. I recommend printing the Spacer part at the same time as other objects.