Make sure to first have SuperBLT, and BeardLib installed. Click the links in the dependency list.

Optional video tutorial for installing SuperBLT, BeardLib, and mod_overrides mods: https://youtu.be/rin_sjSJIkg

1. After downloading the mod, use a program such as 7zip or WinRAR to extract the main folder of the mod.
2. Move the main folder of the mod from step 1 to the Maps folder. Create the folder if necessary; BeardLib should create it automatically when launching the game with it.

You'll find the map in the "Custom Heists" contractor within the contract broker.