Don't worry.
Please plug your trisquel USB again and boot it.
Do not install trisquel. Select try without installing.
After you are in please install Gparted (I don't remember if it is installed
already) and then open Gparted and send me the screenshot.
Also open the file manager and send me screenshot of the devices you have
connected.
If you can't find the option don't worry send me screenshot and I'll tell you
where to click.
Grub is the bootloader is just a program to start the operative system. It
can select between windows trisquel or anything else you have.
But first I want to know where Trisquel was installed.
As a note when you see error or warning messages try taking o picture of them
so we can know exactly what is going on this are not meant to scare you, but
to help you find a solution.
Instead of warnings they should be called information messages.
