Basically you want to disconnect the negative terminal from the battery and wait 2-3 minutes for the airbag system capacitors to discharge.
At the back of the steering wheel there are two holes with 10 mm bolts that hold the airbag in place. You'll have to turn the wheel so the hole is at the bottom to give you more room to remove it.
With the bolts removed return the steering wheel to it straight forward position and pull the airbag away from the steering wheel far enough to disconnect the two connectors on the back of the airbag by pinching the sides. Then disconnect the white connector from the clockspring itself. Always place an airbag with the back facing down.
Remove the steering wheel 13 mm bolt (manual suggests you not to re-use it) use a steering wheel puller to remove the wheel.
With the wheel removed there are 4 philips screw that hold the steering wheel backing.
Either order the backing with holes for the switches or dremel out the holes as in pics.
The switches should be placed with the connector at the top, facing the center, black switch backing on the left side of the wheel and white on the right.
The switch harness runs along the top of the backing with the connector for the clockspring coming from the left side as in pics.
Replace the steering wheel with bolt torque at 65 Nm. Connect the switch harness, white connector to clockspring and the two airbag connectors. Place and bolt up the airbag. Enjoy your new switches.
Here's the pics