The buttons are on the steering wheel, the bcm is the controller of the cruise (and other high end functions you may want later).
Flip down the glovebox, then flip down the front fusebox to reveal the bcm, it should have a label on it that has a big 2 letters at the end, high spec is cd, cj etc, you can post a picture of the label or post the numbers.
It's in the first bit of the other post i linked.
The wires are easy, remove the lower steering wheel cowl and the connector located at 6 o clock is for steering and horn and airbag, you want pins 4 and 5 in the middle of the block.
56 350 2.2 130ps mk7 with 2 side doors
65 290 2.2 125ps custom with 2 side doors
07 350 170ps
Ids v86 licence + v86.04 update + xprog
hereIds map
here