To install into Game Maker: 1. Launch Game Maker using Run As Administrator. 2. Resources > Select Extension Packages. 3. Click "Install". 4. Click "Install" again. 5. Browse to the location of the AutoFullScreen.gex file. Select it and click "Open". 6. Click "OK". 7. AutoFullScreen should now appear under Available Packages. If so, it is installed and available to Game Maker for use in creation of Game Maker game projects. To add the extension in your game project: 8. Select AutoFullScreen from the list of Available Packages and click the Arrow button to move it to "Used Packages". 9. Click "OK".