I cannot get Why3 to run on my system

Your options are:

1. Use Linux in a virtual machine such as VMware player or VirtualBox, and simply follow the instructions. If you are fine with using a machine you did not configure yourself, you can download this virtual hard disk (usable in both VMware and VirtualBox) containing a Debian Buster installation. Use the password "user" when asked.

2. The pre-packaged distribution can run on the C&CZ shell server lilo6.science.ru.nl, on which you can work remotely. To do that, you will of course need a SSH and X11 server (i.e. PuTTY and Xming), instructions for that can be found here

   The steps to install it on lilo6 after that are fairly simple. At the lilo6 prompt:

   $ wget http://cs.ru.nl/~mschool/swan2019/why3-distro.tar.xz
$ tar xvfJ why3-distro.tar.xz
$ export PATH=$PATH:$HOME/bin
$ why3 config --detect
   

   Please note that lilo6 is a shared resource for the entire faculty.