How to install (.py file):

1. Download "RandomizeMaterials.py" .. If it opens in browser instead right click and save as.
2. Open Blender
3. Edit > Preferences > Add-ons > Install
4. Find "RandomizeMaterials.py" on your disk
5. Check the add-on box.
6. Done

How to install (.zip file):

1. Download "RandomizeMaterials.zip"
2. Unzip it, you should get "RandomizeMaterials.py"
3. Open Blender
4. Edit > Preferences > Add-ons > Install
5. Find "RandomizeMaterials.py" on your disk
6. Check the add-on box.
7. Done