"How to play on Android" has its own FAQ section...
Just scroll up a bit, above the Dev Log & Downloads section lies your answer.
Viewing post in Harem Hotel (18+) NEW UPDATE! comments
As the basic installing process is the same on PC, DL the update-zip, unpack and copy the files/folders over to the full install folder, overwrite files, follow the rest of instructions to launch the game.
No garantees, though. This _should_ work, if for whatever reason it does not, you might have to DL the full game again.
Doing it via PC/Laptop and shoving the files over via USB might be an alternative ;)