Installing Generalaire 1042 humidifier?
 

Is this something the average home owner can do themself or do I need a professional? Does anyone have experience installing one? HELP!!!

Depends on whether you have sheet metal tools/mechanical skills. I have installed dozens of them. They are not difficult to install if you have GOOD mechanical skills. Otherwise call a Pro. Post some pics of the front and sides of your furnace and the ductwork attached to it and we can let you know if it is do-able. You need a open floor drain nearby for the overflow or a condensate pump attached to your furnace.