Okay, I know this is a bit long(but it's easy, I promise) and it should work so please try it if you have issues getting the game to run!
So... I was having a lot of trouble with the installation and this worked for me:
I have Disk_1.iso and Disk_2.iso
I extracted Disk_1.iso to a folder, no mounting(!), and explored the folder
---> opened SetUp.ini and I changed(I removed 5 entries and updated the line "Max=18" to "Max=13") the file-list at the end, so it looked like this:
[Application]
Company=Overflow
Name=SCHOOLDAYS HQ
Icon=icon.ico
Version=1.00
Script=1.00
