SIYI A8 - MavLink OSD - for FPV app

I have my SIYI A8 connected to my HereLink Air Unit using ethernet.

The SIYI FPV app supports OSD, and has a configuration option to select “Mavlink OSD.”

I couldn’t find anything in the manual about what connectivity is required for this.

I’m guessing that I need to have a Telem port on my cube’s carrier port configured as Mavlink, and connect that to the A8’s UART. But that’s just a guess.

Can someone please direct me to the proper procedure?

Thanks you!