should be 12mm 12 point box wrench on the t case flange, torx bit up front, not sure what size.
You can put a large screwdriver in the CV yoke or U joint to stop it from moving, depending on your truck (if it wants to turn, 2wd, hubs unlocked, open diff, etc) this is a good way so you can rotate it, remove bolt, rotate....
hve some tape ready to hold the caps on the front U joint so yuou dont have needle bearing issues.
they can be a bear if its factory, so penetrating oil now is a good idea