Press little metal locker to unlock inner ring with bulb.
Pull out the inner ring together with the bulb outward
For this step you will need small flat screwdriver.
Unscrew the two screws to disconnect the bulb
Remove an old bulb and put a new bulb into inner ring.
You need GU5.3 (or MR16) halogen lamp.
Do not use LED lamps instead of halogen as different power source is needed.
Insert a new bulb into the lamp holder socket and tighten the screws
Insert the inner ring into the mount on the ceiling. Remember to insert the lug of the ring into the holes of the ceiling mount.