Fixing Steering wheel alignment after replacing clock spring

How do I center the steering wheel? My third party mechanic replaced a broken clock spring (spiral cable) and now new clock spring and steering angle sensor is broken (likely due to over stretched due to steering wheel and clock spring not aligned properly). steering wheel is off center driving down the road, it used to be straight. I dont trust him anymore and want to fix it myself.

I dont want to break another clock spring and angle sensor, i have a generic $90 ebay set on its way to me. I have heard to turn the wheel all the way one way, mark at 12 oclock and turn the wheel all the way the other direction, mark the second 12 oclock spot. finally recenter at 1/2 the number of turns to the middle. Wondering if this is the way to do it.