No hardware or glue is needed, the pins are friction fit into the tight link. The dimensions are pretty tight so you may need to scale the pins up or down a few % depending on your printer. There are a handful of lids so it can be used as a storage box, piggy bank, or trash can. For trash use, there's a hinged print in place lid and a ring to clamp the bag in for retention. To use a pet waste bag as a liner just lay the bag out flat, measure the width of the bag, multiply that by 2, then divide that by Pi, and subtract a few millimeters to give enough space to roll the bag over. Scale the x/y of the drum and parts to match your chosen bag.

To assemble the locking ring. slid the lever over the closed hole on the locking ring and put a short pin through it. Take the 2 link pieces and put the side with the standoff towards the lever and put a long pin through the links and the middle hole on the lever. Then put the last long pin through the remaining open hole on the links.