Can't Get Radar Overlay

[jmreim11]

Hello - I have a new Axiom RV (LH3) with Navionics charts and a new 18" radome Radar that seems to work perfectly on it's own.
I'm having difficulty getting radar overlay to display.

When cruising (7+ kts) and in Charts, I go to Layers and then turn on Radar layer switch. I then get a message that says:
"Warning - Radar overlay cannot be displayed.
Either:
- fit heading sensor
- Select "use COG" in the "Radar without heading" setting in overlay settings
and maintain sufficient speed to give accurate COG"

Any idea what this is about and how I might fix it? Hoping someone can point me in the right direction. I'm new to this forum and not sure I'm receiving responses from any of my posts - perhaps I have something set wrong (or members are just astounded by my ignorance).

Thx -
Jim