Cam Cleat Install

[ThreeQrtrTime]

My boat uses a Jam-Cleat on each side of the cockpit to hold the traveler car in place. Frequently, the line comes out and the traveler flies to leeward. Arggggg.

I purchased two Harken 238 Cam-Cleats with Fairlead to replace the Jam-Cleats. The Cam Cleat has a pre-drilled metal plate. My question is, does the plate go under the Cam-Cleat and I need to do some for of backing or is the metal plate the backing plate. Looked for installation instruction but found none.

Thanks