1) You'll find this under "Security & SD-WAN" -> Appliance Status -> Uplink
There you can change the IP from DHCP to Static.
NAT will be automatically done for all outgoing traffic.
2) This is done under "Security & SD-WAN" -> Addressing & VLANs
There you can decide if you want to have multiple VLANs, configure your internal IPs and also set static routes if you have VLANs on the internal switch.
If you found this post helpful, please give it Kudos. If my answer solves your problem, please click Accept as Solution so others can benefit from it.