how do you adjust the clutch where is the bleed valve or screw on 1993 GMC Sonoma

it doesnt happen a lot i forgot to check the fluid

Asked by for the 1993 GMC Sonoma
Bleeder is on the slave cyl. under truck at trans. Takes an allen wrench (i think) to turn it. It dont look like the bleeder screw on a brake system. Not adjustable!