1- Unzip
2- Copy the folder "Michele71_Script"
3- Paste then into your folder Scripts in Max (like "C:\\Autodesk\3dsMax2010\Scripts")
4- Start 3DSMAX and run script "Quick_Z-Depth.ms" inside the folder "Michele71_Script"
5- Go to "Costumize" > "Customize user interface" > "Menus"
6- In "Category" find "Michele71_Tools" and choose "Quick_Z-Depth"
7- Create new menu in list "Menus" and Drag and Drop the new menu in the "Main Menu Bar".
8- Drag and drop "Quick_Z-Depth" in new menu.