Take the old cable off at the helm end and feed it out of the console. Undo the tie-bar nut on the other end of the cable, which probably runs through the motor tilt tube and disconnect the tie-bar, then undo the big nut which secures the cable to the other end of the tilt tube. You'll probably need to cut loads of cable ties, etc. to free the cable from the rest of the wiring, cables, etc running from the console to the motor(s).
Now the fun starts!
On a twin engine rig, you'll almost certainly have to lift up the motor the steering cable is connected to (probably stbd hand motor), in order to get the cable free - sometimes you can just tilt it over sideways, but all the mounting bolts will need to come out in any case. A 60 2-stroke isn't too heavy, but it will be awkward, so probably best to have a mate to give you a hand.
If the cable is rusted into the tilt tube, then this will add further to your fun.
Plenty of previous threads on here, on that subject.
Not a technically challenging job and certainly not one that anyone handy with spanners and hammer would need to refer to an outboard engineer.
Good luck!