I have a bryant unit heater in my garage it is a 60,000 BTU model 75-347. The fan will run but I don't know how to light the pilot light.

Is this a unit heater that hangs from the ceiling?

If so there is a valve you can see on the back of the furnace, there is a knob on top that says On, Off, Pilot. After you have made sure that there is no cutoff in the line that services the heater, Turn the knob to pilot light, look for the pilot at the other end of the 1/4 inch tubing, hold a match to the pilot and now press down on the knob, make sure it is in the right position or it will not press down, hold the knob down for about 45 seconds, the pilot should stay lit. Move you face away from the heater and turn the knob to the on position.'

I hope this helps.

Thanks for the reply, but it turns out after trying almost everything I found a screw on the back that said pilot adjust with a set screw inside that when I unscrewed it the pilot lit first try, and the garage is now a perfect 60 deg.

You may want to take the pilot assembly apart and clean the orfice,it may have some junk in there requiring more gas pressure to keep it lit.