We have those manuals: https://trisquel.info/en/wiki/installation-guide
Checking whether the instructions still work (if not, correcting them) would be nice. In particular, the last update on https://trisquel.info/en/wiki/install-trisquel-windows-dual-boot-0 is almost five years old.
But that requires having at hand an installed Windows/Mac/Ubuntu system, what many of us have not.
