For more info watch: https://youtu.be/PjOyAcW-Fic
This is an open source project. All the step files are provided for you to download for the purpose of making the assembly easier and so you can easily modify the design.
The only things you are going to need for the assembly are:
-3 2mm pins, you can just take anything with a 2mm diameter and cut it to the right lenght
-some M3 screws and two M3 nuts
-some threaded insterts I used these ones
-a pull spring or if you can't find one, a rubber band will do fine too
The author stlcove has offered the item for free, you can now download it.
Download