Connecting 2 Firewalls with SXT G-5hnd

Is there a step by step guide for connecting 2 (Zywall) Firewalls with two sxt g-5hnd antenna’s?
I’m stuck how to deal with the routing process, and 'now don’t know how to configure the ip adresses for the WAN and lan on both the firewall and the antenna’s. I attached the situation. Please can someone help me what to fill in the best on the question marks.

Thanks,
Dennis
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