New installation,

Hello everybody,

I'm new on this forum, and i have acquired the free edition of astaro security gateway, version 8.202. I have installed on a PC with 3 ethernet ports, one for the WAN, one for the LAN, and one for a DMZ.
I was be able to connect to the webadmin interface with my favourite browser.
First impression:whaoo, very impressive, even in this free version.
I connected my box on my WAN port, and my switch on my LAN port, but no internet connection on any PC in my LAN. No problem with the IP of the differents ports, i have already installed another firewall software, i am kind with the subnet , gateway , and the DNS.
I tried to create a bridge between the WAN interface and the 2 other interfaces, and the internet connection works on the LAN. But i am not sure that it is the best way to have a secured connection. I have selected some protection rules on the setup of astaro, but i don't know if these rules are applicated to the bridge have created.
Can i have some explanations to create a secured connection in astaro, i have already read the manual , but nothing is explicitely explained.

Thank you all,