Please connect one of the 2 telemetries to the "Telem 1" serial port of the Pixhawk.
Then you can connect the other telemetry to your PC via a micro USB cable or to a tablet via an OTG USB cable.
IMPORTANT: Do not forget to screw the antennas on each telemetry module before feeding them, otherwise the HM-TRP chips can be broken.
There are 3 LEDs on the telemetry module. The blue led indicates if the module is powered. The green led indicates if the telemetry module is correctly linked with another telemetry module. The red led indicates if the module is transmitting data.
In nominal operation, the blue led is on, the green led is on, and the red led is blinking.