Well ideally you need 2 people, one sitting in drivers seat and other at the caliper.
Check the fluid if topped right up to the brim of the reservoir, then get a spanner on the bleed nipple and a piece of clear plastic hose and attach it to the nipple, find a suitable container (an old milk bottle is my choice) and 1/3rd fill it with new fresh fluid. put the open end of the hose into the bottle making sure its end is below the fluid level.
Crack open the nipple with the spanner about 1/2 turn and get the person in the car to SLOWLY push the brake pedal down to its limit and hold it there, then you tighten the nipple (not mega tight just nip it up) and then the person in the car can release the pedal (slowly).
Repeat this process until no more bubbles can be seen coming up the pipe.
Remember to keep an eye on the reservoir level.