Welcome sister Mariagrazia.
I am sorry for your back. I guess it's a painful problem and and not easy to solve, however, I hope that the back problem can be resolved as soon as possible.
It's good news to know that you want to try to install the Linux operating system on some sister computers.
Feel welcome and if you have difficulty with any of these computers don't be afraid to ask for help. Here there are many competent users who are committed to helping users in trouble.
If the church/convent is located in a somewhat large city you can also count on the help of the Lugs association.
http://www.ibiblio.org/mirror/www.linux.it/LUG/
They typically have a office that is opened one day a week to help users in need. Usually the user in difficulty goes to the lug office, but you can ask that someone come to the church/convent, if it is not too far.
You will also have seen that there is an Italian section of this forum,
viewforum.php?f=14
if you prefer to ask for help in Italian.
Considering that you have studied computer science, perhaps you can be the one to help others, now or in the future.
In the meantime we hope God will help the world to heal from viruses and human greed/dullness.