Runcam Thumb Pro start recording on WP

Hello Guys! I need help with runcum thumb pro on auto mission.
My new camera is still on the way, but I already know that it is controlled by pins RX and TX for recording video.

I know that i can start video recording using radio control equipment, but how can I start video recording at a certain WP in the auto mission?

I will need to turn on video recording at the point and turn it off at another point
im need use cameratrigger command or what ?
I will be grateful for the answer