How to connect Simplertk2b and telemetry to pixhawk 1

I have autopilot pixhawk 1 (pixhawk 2.4.8).
I need to know how to connect the simplertk2b to pixhawk: by the jst-gh port , to pixhawk gps port, using a jst-gh to DF13 cable?
And, about the telemetry radio : the Air module must be connected directly to the simplertk2b , or it must be connected to the telem port of the pixhawk, and the NTRIP corrections arrive to the simplertk2b passing through the pixhawk?
By the way, i have a second gps (m8n) with compass, can i use it as second gps (for the compass, but also for blending in case the simplertk2b failures)?
Thank you!