H.323 Extension

I installed Asterisk on a Raspberry Pi and configure it with Freepbx.
A SIP-Phone already works great and now I want to use a H.323 Phone.
I created a new Extension (Other Custom Device) but I don´t know what is the right configuration.
In my phone there are the following settings:

Registration to gatekeeper mode -> OFF, MANUAL, AUTO
Gatekeeper IP address ->
Time to live (second) -> 180
Faststart -> NO, YES
Tunneling -> NO, YES
Alias E164 ->
H323-ID ->
Hold and transfer according to H.450 -> NO, YES
DTMFRelay -> OFF, IN Band, OUT of Band, AUTOMATIC

What do I have to choose here?
What is the “Alias E164” and what is the correct “H323-ID”?
I already installed the following module and tried different settings, but my phone displays “GK link down” all the time.
The Phone is a Swissvoice IP20.
As you can see, I have many questions and not much experience with Asterisk.
I hope that you can help my with that problem.