1994 Ford Explorer replacing ball joints and reinstalling s

Tires and Wheels problem
1994 Ford Explorer Four Wheel Drive Automatic 175000 miles

I removed the steering knuckles because a wheel fell off and ground the lower ball joint down to the knuckle. I cut off the castle nuts with a sawz-all and got new ball joints pressed in. How do you get the knuckle back on with the spindle inserted and the ball joints on? It seems like an impossible rubik's Cube. What's the trick?