Best way to configure a Pace 5268ac with a Ubiquiti USG and Cloud Key

What do I need to do in order to set up a Ubiquiti Unifi Security Gateway(USG) with a Pace 5268ac Residential Gateway? I can't seem to get an internet connection when I plug into a switch behind it, but I'm fine if I plug a switch into the RG by itself. I must have to do something to the Pace in order for the USG to work(bridge it?). 

Any help is most appreciated. Thanks.