You have to wait for the night, turn off all lights in and on the car and drive 20 km at atleast 100 km/h or 30 km at atleast 60 km/h.
If you completed the required kilometers, you have mastered the challenge. Now, you gotta upload a video of it on Tiktok.
If you want to do the Blue Whale Challenge, first off, dont. Do this instead. Please. Don't kill yourself. Please don't. People care. They really do. I promise.