Where can I find the register configuration for OV7251?

I would like to know the correct register setup to switch the OV7251 image sensor into External Trigger mode. I am looking in the ArduCAM/MIPI_Camera GIT repository, but I cannot see where it lists the register configuration for this image sensor.

Does the ArduCAM/MIPI_Camera repository contain the register set up for the OV7251 sensor? Where can I find this information?