Tunneling LAN port to WAN

Hi,
I have RB493 running MikrotikOS 6.7. I have WAN port conected to my ISP modem and few LAN segments on diffefent eths.

On one eth port I have single device I’d like to connect directly to WAN to get public IP from my ISP etc. How should I do that? Sorry if it is a silly question, but I am NOOB to any advanced routing device. Thanks a lot.

bridge wan port to the lan port
(but i guess that you will want to share the internet connection to the other hosts, in which case you will want some sort of a DMZ)

Yes I wanna share i-net connection. Esp I do. There is NAT for al other LAN segments. And one more thing. Id like ti use Firewall even fot that device in DMZ zone. SO bridge is not what I am loking for, I gues. Or is it?