Basic problem creating configurable part

I'm just starting to use the design library/toolbox andhaving some problems.

I'm trying to create a part with 2 configurable dimensions. I wouldlike to insert the part into assemblies and have it prompt me witha window (edit toolbox definition window?) for 2 user defineddimensions. Each unique dimension combination would thus create anew configuration for the part.

Is this possible? I think so. How? Do I use the design library ortoolbox?

SolidworksToolbox