I posted to the wiki the directions:
https://trisquel.info/en/wiki/installing-virtualbox
Also here they are:
Note: this applies for at least Trisquel 6.
Trisquel Menu > Accessories > Terminal
Copy and paste each one of these lines into the terminal one at a time and
hit enter at the end of each pasted line:
sudo apt-get update
sudo apt-get remove virtualbox virtualbox-ose --purge
sudo apt-get install linux-headers-`uname -r`
sudo apt-get install virtualbox-ose
sudo adduser $USER vboxusers
After you have run these lines in terminal log out and log back in.
Feel free to post below why you dislike Virtual Box and directions on
alternative applications.
