How do i replace the dome light in my 97 corolla

The dome light is mounted on the ceiling of the car.
You would need a small flat-end screw-driver, and aim it to the base of the lens cover. Then pry the lens off.
If you cannot remove the bulb with your finger nail, then pry it out at its end. Or simply push back the bulb's contacting spring at the end of the bulb. Then steady your hand to catch it as it drops down.
Replace the lens by pushing it back to its housing.
Test the dome-light if it works. If it doesn't check the dome's door switches screwed to each door frame. Pushing on the door switches several times sometimes refreshes the dome-light. The door-switches can be removed with a medium-size 4-corner screw-driver.
By removing the black covers of the door-switches, their conditions could be detemined. Spray some electrical contact-cleaner on them if corroded, or simply replace with new ones.