I had the same trouble, but the solution I found is :
- open the text file and copy the weblink
- go to internet with this link and download the file (MEGA works fine), it is long if your connexion is poor (as mine) but it works...
- unzip the donwloaded file
- move the unzipped file into the directory where you already have the first chapter of the second season
- this should be, from your home directory : /Library/Application Support/itch/apps/medieval-times
Note that the directory Library inside your home directory is not visible directly (and it is not the same Library as the one under the root directory of the computer) ; you must go there from your home directory with the command "go to" or "go to directory", I do not know exactly how it is labeled in English (not my native language).
I hope that can help.