I fitted a jefa linear arm to my 2004 cruiser 36 utilising the jefa supplied tiller arm bolted to the rudder
Stock underneath the quadrant
The arm was true bolted to the bulkhead near the inspection hatch to the transom on the port cabin
Very straightforward , easy and worked well
I like an AP to be completely independent of the manual steering components so I would not use the chain drive system suggested up thread. ( it’s also expensive and much harder to install. )