First of all, you need to do this from a PC, and link your phone to it... I've no clue how to do this strictly from your phone, or even if it can be done. Unzip the archive to get three files... the .apk, the .rpa archive, and the "how to install" .txt file. link your phone to a computer, and manually load the APK into your download file. STAY CONNECTED. open your phone's download file and load up/install the apk... allow it storage, and immediately close it out. Back on your computer, back out to the file list and go to "documents". there should be a new file that says Ren'py saves (or similar) open that. You'll see "Lucky Paradox" folder. Open that, and you'll see some loose files and a "game" folder. open that. it should be empty. copy/paste the .rpa archive into that. When the whole thing is done (may take a minute as the .rpa archive is a large file) close it all out, safely un-link your phone, and go back to the Lucky Paradox icon that should be in your other app icons now. you should get the opening pic... give it a sec to load, and you should see the language selection screen (flags)... click on the English (US/UK) flag, and BAM... Disco.
This is all explained in the "how to install" file.