1: Download the map/mission/campaign you want to install and unzip the folder. 2. Navigate to VTOL VR inside your Steam library and right click on it, click Properties, and then Local Files, then click Browse Local Files. 3. A window will open in VTOL VR's installation location, move your downloaded custom maps into the Custom Maps folder and your downloaded custom missions into the Custom Scenarios folder. 4. Start the game and enjoy!