There is a wiring harness that runs down the center of the steering column (and out through a nut on the steering box). You should start by finding the end of it, near the horn on the drivers side and disconnecting the 4 wires from the main harness. Remove the subharness from any clips and lay it out in front of the car.
Then there are three small slotted-head setscrews in the steering wheel hub that have to be backed out by 1/8" or so (or just remove them entirely). Then the entire control head assembly (horn button plus turn signal switch) should pull away from the wheel, pulling the subharness along with it.
Your choice as to whether to pull the wires entirely out of the steering column, so you can carry the control head to a better place to work; or just pull out a foot or two and work sitting in the driver's seat. Fishing the wires back through the column (and stator tube) is not the easiest thing, so I usually just spread a large white towel on my lap and sit in the driver's seat. Of course, if the stator tube is broken (allowing the head to turn), then you'll have to pull the wires out anyway to replace it.
On the back of the control head, you'll see a large round plate (which is the piece that was trapped against the steering wheel by the 3 set screws). The plate has 3 holes. Turn the plate until the holes line up with 3 flat head screws and undo the screws. That will open up the area where the connections are made.