As Mulf says, if you buy the Lewmar power-kit, you will have very little chose how this goes together.
Our L44 halyard winch is powered. The motor sits DIRECTLY attached to the bottom of the winch. It is about the size of a 16oz soda bottle, and is oriented 90 degrees to the axis of the winch. (see pix)This cannot change, but you can rotate it in any direction to make fitting easier. The hull liner had to be cut for ours to be fit, and the installer made a small teak box that covers it in the aft stbd cabin.
Wiring of the winch and relay is pretty much by the instruction manual. Follow the wiring sizing guide to the letter. The switch can go anywhere, but best close to the winch.