Helm vs tiller arguments aside, I guess you want a remote helm for a reason, so.....
The steering bowden cable (big thick thing from the wheel) needs to be anchored to the hull or engine. An '86 Merc might not have the feature i'm about to describe, but if it does, stuff the end of the cable through the starboard end of the big hollow tube that the engine tilt pivots round. The big nut on the end of the cable sheath fits to the thread on the end of your tilt tube. If your tilt tube is a "simple hinge" and doesn't have a big hole / threaded end, you will need to buy a transom anchor for it & fix it on with suitable bolts just below the engine To put the anchor nut at approx the Stbd end of the clamps.
The "moving bit" of the cable should now be to the port side of your engine. Have a guddle under the engine at the centreline. You should find either a "tiller" with an approx 1/2" (10 or 12 mm) hole, or a couple of forward facing holes in a casting. This is what you connect the "drag link" to. If you have a single veritcal hole, bolt the connecting rod (AKA drag link) to it. If not, you'll need to source what is essentially a bent bit of thick plate that bolts int othe casting and gives you the hole I just described i nthe last sentence. Other end of the drag link goes into the hole in the end of the moving bit of the steering cable.
Any Merc dealer should be able to sell youa drag link. A wee trawl through / "wanted" ad in the Bits'n'pieces section here should find one.
If you need the bracket, plenty of the "used engine" delaers will have old ones going for a lot less than a new one, if you can even getg them new...
Then just fold the tiller up out the way & you can use it as emergency steering / throttle etc .
Have a look at the "best wake shot" thread in the photos section - plenty of pivcs of engines on the transom to give yo ua better feel for it.