To install a zip package:
1. Download the zip package from https://maciejrogowski.com/catalog/
2. Unpack the zip package in the AddIns folder:
Windows: C:\Users\[username]\AppData\Roaming\Autodesk\Autodesk Fusion 360\API\AddIns\
Mac: /Users/[username]/Library/Application Support/Autodesk/Autodesk Fusion 360/API/AddIns/
or in any other new folder.
3. Open the Add-Ins dialog window in Fusion 360.