Migrating from Untangle to FWG

I know this topic has been covered in passing in prior posts, but I feel I'm still missing something.

I am migrating from my old firewall/router (Arista Untangle), and want to make sure of two things:

1) My 20 static IP entries are ported to the FWG

2) I'm still able to use AdGuard Home for my DNS server

So far, I've plugged in the box and just connected it to a spare port on my switch. This was enough to get it recognized, update firmware, etc. However, I'm not sure what to do next.

My existing network is on 192.168.2.1/24. Should I first set the FWG to this same network? I'd like to get all the static IPs setup before switching over, but maybe that's not possible?

Thanks for the help!