Power Supply Replacement,Dimension 4500

I have just ordered a refurbihed power supply, 0N380, PS250 watt, Non PFC,20+4, 1 watt , for my Dimension 4500, as the fan noise is really bad.

Is there a place I can go to to see the mechanics of installling it? I think I can do it, but followiing directions is much easier.

Thanks,

Mr. Yates