This print is designed to use 1.75mm filament as its spring. Insert filament into the holes in the base and add the clip on top.
Print the base as heavy as possible, or pause the print part way through and fill with sand or lead shot to weigh it down on your desk.
Use Zip ties or fishing line to affix the mouse cable inside the bungee using the provided holes.
The author hasn't provided the model origin yet.