Transparent Firewall setup?

[Nnyan]

I have a new deployment that I need to install an inline firewall/url blocker with no NAT, traffic shaping or routing of any type (Transparent Firewall/bridge/???).  I would like to use OPNSense and after doing some research believe I need to follow this guide:

https://docs.opnsense.org/manual/how-tos/transparent_bridge.html

I don't want to make any changes to the clients if I can, I need to use the current device as the gateway/router/dhcp/etc...  and only want to add an additional layer of protection.  Thank you all in advance and any help will be greatly appreciated.