hello, sorry to answer so late, it may be of no help anymore. Anyway, I have already posted this text to someone else, I copy it here (the explanation is for Mac users, it may be somewhat different for PC or Linux) :
The file is a textedit file, with a link to a web page. Copy this link into your internet browser, go there, and download the file (it may take time). Then unzip the downloaded file. Move it inside the following directory (create it if "medieval-times" does not already exist, all the other ones must already exist) :
Library/Application Support/itch/apps/medieval-times
This Library is NOT the one under the root of the computer (on Mac at least) ; it is under your home directory and may be not visible (you can reach it with a command such as "go to ..." in the upper bar).
I hope this can help.