Smith Machine - Proper Use?

Question:

The club where I work just got a new piece of equipment called a Smith machine. Most of the members don't know what they're doing. Do you have any information on the proper way to work the Smith machine? I've never cared for it myself as it's too hard on the knees if not properly instructed. I had a member ask why it's easier to lift more weight on an incline chest press with the Smith machine than it is on a flat bed Smith machine chest press. This same man refers to himself as having a greyhound stature. He is about 49 years old, lean and mean. He wants to know why he can work the hell out of his legs and not get sore on the Smith machine, but when he works his upper body, he feels it.

.......