Go to Interfaces/Assignments.Are all 4 interfaces listed?If not, select one in the drop down at the bottom and click add. Do the same for the other.Now click on an interface you just added and assign name/IP/etc.Don't forget to enable it too.
It's just getting used to where things are.In your case DHCP service. Go to Services > DHCPv4 . There you set each interface as you want. Range, etc.You need to have assigned the interfaces at this point.Similarly for the firewall, the rules are set for each interface.