Taskjuggler

A simple search on the Web returns https://rubygems.org/gems/taskjuggler

So, apparently, once you have Ruby installed and launched, taskjuggler is one command away:
gem install taskjuggler

Thank you Banana.

Thank you Banana
The Taskjuggler version 3.5.O was successfuly installed with this command on Trisquel 7.
Now, about graphical connexion to Taskjuggler. The problem mybe is Taskjuggler is not ported yet on graphic way.
If you have time to help me to connect with.
Many thanks.

I have never used taskjuggler. Maybe you want to use it through Redmine: https://github.com/chris2fr/redmine_taskjuggler

Or maybe you want to try a recent fork of Redmine: https://www.openproject.org

Thank you very much M.Banana
I utilize to teach Taskjuggler in Management of Project with Trisquel 6 & Gnewsense but with Trisquel 7 only gem install is possible. After a successful installation, I have a problem to utilize the graphical way to access to Taskjuggler.
So thank you.