Noob question here:

Got into Revit recently, and am learning families. A few Q:

1. Can someone point me to a good explanation of the differences between the different "Generic Model" family templates? Can't find anything out there explaining the differences.
2. I'm having trouble placing a "Generic model family type" component that I came up with into the project where I want it to go. I'm trying to understand how the component is placed when I load the family into the project. I DONT want the object associated with a wall, roof, or other project object; I want it to attach to an intersection of two reference planes. However, when I choose "pick a plane", it still wants to attach to a physical object.

So...

How does Revit decide what to attach a family type to in a project. Can I choose some sort of "base point" when I'm editing the type object, which will then be used for placement in the project?

Thanks