I agree with Moseso, easier to assemble the wires to the control head (especially since some of the screws for the wires also hold the control head together) and then insert the wires through the stator tube & column. But it can be done the other way:
Pull the wires up to get a foot or two of slack, then sit in the driver's seat with a towel on your lap while you do the final assembly of the control head. If you are lucky, the towel will catch the tiny little parts that you're bound to drop at least once. (If you're not lucky, you'll wind up having to remove the seat to find that it bounced into the door pocket
Anyway, once the wires are attached and the head is fully assembled, turn the steering wheel to it's straight-ahead position, and turn the canceling ring on the control head so the tabs are pointing straight down. The gland nut on the steering box should still be loose at this point, and the stator tube pushed as high as it will go without going through the compression ferrule. If you have an adjustable steering wheel, set it as far forward (close to the dash) as it will go.
Pull the wires through until the control head engages with the stator tube (dimples in the slot) but don't push it all the way against the wheel until you turn the head & stator tube to the correct position (centered turn switch straight up) without turning the steering wheel. This is important for proper canceling. Once it's all lined up, you can push the control head home against the wheel (which will also push the stator tube through the gland), and tighten the 3 grub screws to lock the canceling plate to the wheel. Tighten the gland nut, and you're done with the mechanical part.