Some advice for beginner

Hi,
I have some other questions. I made some test on SITL where I’m capable to send/receive messages through a bridge Serial/UDP from the simulator to LoRa device and vice versa. I would move on to a real environment, at this point I have:

PixHawk 2.4.8

stm32 Lora Device

GPS/Compass u-blox M8N

I already linked the stm32 to pixhawk through telem1 port, the configuration which I made is:
MAV_0_CONFIG: TELEM1
SER_TEL1_BAUD: 115200 8N1
But I can’t read messages on stm32 device yet. I don’t know why.

For GPS I just plug in the port.

Can I use the HITL and see data from GPS on QGC?
Can I receive the packet on STM32 LoRa linked directly on the pixhawk or have I to connect the stm32 device to PC to receive data from pixhawk?

From STM32 lora device have I to send a heartbeat message to receive data from PixHawk?
If yes, whit which parameters have I to fill the message heartbeat?

If the pixhawk is connected to the pc it is possible to read mavlink message on stm32 linked to the pixhawk or have I to disconnect from pc the pixhawk?

I made a lot of questions, hope you can answer me.

Thank you very much