configure firebox x750E for network

Hello,

This firewall is a Watchguard firebox x750e. there has been a change within watchguard to where the old firewall's policies are configured and named differently than the companies older model firebox. I can't import old policies so i have to start from scratch on the new one.. I am looking for advice or a best practice for setting up this firewall in a medium sized enterprise.
Should I use a proxy or packet filtering. Any ideas or things to read online?
Sincerly,
Ryan