Do you have a PC? Mac? Or Android?
Hallo, RD Ace. Since the question seems to be lingering, allow me to shine some clarity on the matter.
Harem Hotel v0.18.1 PC/Android12 GB
Harem Hotel v0.18.1 PC/Android (Mirror)
Above are the names of the two links in which you'd want to concern yourself with. The latter link is simply a mirror, an alternative site to download the game from in case the first link isn't working for some reason. You can find them easy by the mark of "PC." I hope this helps.
To give an explanation anyways: that is an update patch file (as stated in the name). It allows you to download only the updated content and apply it to your already downloaded game, that way you won't have to download the entire game again. It'll have instructions within the downloaded files on how to apply it, too!