You have to download the APKs for joiplay and the renpai plugin (both are on the joiplay website), then download the windows zip file instead of the APK on this page, unzip the file, then in the joiplay app find the unzipped 'adastra-17-win' file, find the .exe file in that folder and select it. Then just follow the prompts on the joiplay app and you'll have the game.