How to use 5G Modem/Router

I have a 5G Modem/Router that has built in Wifi and two LAN ports out of it.

So, I need to add a further Home Wifi router, and have a setup something like this:

5G Modem/Router <-> Nano <-> Home WiFi

Will this work, do I need to open up port forwarding ports on the 5G Modem towards the Nano and also from the Nano to my Home Wifi ?

I think it will work no need to open any port. just connect 5G Modem/Router --> Deeper Mini --> WIFI router