Place Sophos XG in Unifi network

I want to integrate a Sophos XG home within my existing network and would be grateful for a checklist of things that I need to do:

external fibre ISP router <> sophos XG <> Unifi <> switch <> ap

The Unifi runs superbly and would therefore like to place the XG in front of this. Some extra notes

- the usg services multiple vlans 192.168.2.x, 192.168.3.x etc, vlan 2,vlan 3 etc

- the isp router cannot go in bridge mode, full nat u

I want to integrate a Sophos XG home within my existing network and would be grateful for a checklist of things that I need to do:

external fibre ISP router <> sophos XG <> Unifi <> switch <> ap

The Unifi runs superbly and would therefore like to place the XG in front of this. Some extra notes

- I don’t want to nat the sophos or ideally the usg

- I don’t want to bridge the sophos XG as I want to use some of the additional features

- the fibre runs at 100mg full duplex

- I run voip successfully at the moment

- I have managed to get the XG running at latest software on 4 port pondesk intel box but not placed in line yet

- I successfully run L2tp through to usg

Your guidance would be much appreciated.

Regards,

Mike

Regards,

Mike