1. Make sure the game is installed via Steam.
2. Download the rar and extract it anywhere. Make sure to open the folder - it should look like:
3. Click on the file labeled 'Kemomusu_Steam_R18DLC.exe'
4. You will see this screen after clicking Next - this is normal. After this screen is done, click next again:
5. Make sure the file path matches your steam install. If so, click Next!
6. You're done!