I can not seem to get the "copy" of a house in my library to go onto a property that I own, what is the trick?

My guess is that s/he has a saved house design and wants to place it on a lot in the city edit mode. Make sure that the lot is set to the right type by clicking the icon with the arrow tool and choose the "edit type" button. Set it to residental for a house to live in, or the right type of commity lot in the list. Every type of community lot (bars, stores etc.) has their own category that must be set on the lot before you can place it.