I am not a Honda tech but I do know you have a few choices here. One is you could replace the defective actuator with a factory OEM Honda actuator. That will involve removing the entire door latch/lock assembly as a whole unit and replacing the actuator. That may or may not be something you really want to do.
Two, you could just unplug the defective factory actuator and then have to lock/unlock that door by hand. If you don't use that door very much, maybe that is a good choice. You should not have to remove the latch assembly to unplug the actuator. It will be a two wire plug, probably will have a yellow/white and a yellow/black wire on it.
Three, and this one is my favorite, is you can unplug the defective factory actuator and leave it in place where it is mounted in the latch assembly. Then you will have to find a way to mount the aftermarket actuator on a more or less horizontal position on the door or in the open cavity near the upper section of the door itself. You can't attach the actuator rod to the factory door lock mechanism because that is an internal and integral part of the door latch assembly. If you were to go that far with it than it would just make more sense to replace the factory actuator.
Up near the top of the door there should be an open cavity where you can put the actuator. The actuator should have come with one or two metal mounting straps. You can mount the strap to the actuator, and use them to suspend the actuator in the open empty space in the door cavity and screw the ends of the strap to the door. Then just use the rod and hardware that came with the actuator to attach the rod to the Honda door lock rod on the door itself. Be sure the actuator and rod clear the motion of the window and don't bind up in the door lock and latch rods. Back when I used to do this kind of work for a living I sometimes had to get creative like that when mounting door lock actuators. Just remember you want the actuator to mimic the motion of the door lock when it moves. So if you mount it horizontally, it needs to extend the plunger for unlock and retract the plunger for lock. Sometimes you have to adjust the mounting configuration a bit to get the right action out of the actuator. Also don't mount it too tightly or the motor can bind up. And you want the actuator to be mounted in an area where it has the smoothest operation and the straightest orientation to the door lock rod at the top of the door/door lock button. You can make a gentle bend in the aftermarket actuator's rod and still have it work OK, but do not bend it more than about 20 to 25 degrees. If there is no open cavity or area at the top of the door, you can cut one out if you need to. The steel is not very thick, and can be easily cut with tin snips or a jigsaw. When you are testing the operation of the actuator and door lock rod, use a screwdriver to push the latch on the side of the door closed. This will mimic the door being closed so the lock arm will operate while you test it. To unlatch the door, just operate the door latch rod by hand.
Once you get the actuator mounted, use a separate 12 volt source to test it. Remove the the door handle pull/door lock button assembly from the door panel and mount it back onto the door temporarily so you can test the door lock system. Close the door and connect a battery to the 2 wires for the actuator, a good one to use is a battery from a cordless drill, most of those nowadays are at least 12 volts. Put one wire from the actuator to the positive terminal and the other wire to the negative terminal on the battery and the actuator should move and operate the door lock. The aftermarket and OEM actuators are both simple two-wire reverse polarity motors. It is generally understood that with 12 volts positive on the green wire of the aftermarket actuator and ground on the blue wire, the actuator will retract (lock). Reversing the wires makes the actuator extend (unlock).
Once you have the actuator mounted and it tests out OK, just connect the two wires from the actuator to the two wires that were plugged in to the factory actuator. If that door lock works backwards (locks when the others unlock, and vice versa) then just reverse your wire connections. Then reinstall the door panel.
I did this exact same thing on my girlfriend's 2003 Accord. The actuator on her driver's door broke and I installed an old aftermarket actuator that I already had on hand. That was over two years ago and it is still working fine now. When her factory actuator broke, it made the lock and unlock part of her factory keyless and central locking system not work at all.
It is not hard to install the aftermarket actuator. It will take some patience and trial-and-error to get it right. If you have trouble with it, any good independent car audio/alarm shop would probably do it for a reasonable price.
