You are lucky!
MICROWAVE OVEN LIGHT Remove the louver per instructions 1-3 above and charcoal filter, if used.
1. To replace light bulb, first disconnect power to the microwave oven at the circuit breaker panel or by unplugging.
2. Open light cover located behind filter mounting by carefully pulling up on the front edge.
3. Remove old light bulb and replace only with equivalent watt bulb available from parts distributor. Bulbs are also available at most hardware stores or lighting centers. DO NOT USE BULB LARGER THAN 20 WATTS.
4. Replace the microwave oven light cover by carefully pushing into place. Replace the charcoal filter, if used. Push the louver back into place (engaging both the bottom and top tabs) and replace the louver mounting screw.
When in doubt, refer to the manual :>D