It’s ridiculously easy. I did this in about 5 minutes.
1. Unthread the lever pivot set screw by using a 2.5 mm allen wrench and turning counterclockwise. Make sure to keep your hand underneath the brake as the screw may fall down suddenly.
2. Unthread the lever adjuster screw by using a 2.0 mm allen wrench. You will not unthread it entirely. After a few turns, you’re ready to move to the next step. You will hear popping sounds. That’s ok.
3. Gently pop the lever out and you are done.
4. Replace with a new lever by reversing the above steps.