Hi guys

I am working on turning a base drawer cabinet into a wall hung vanity for the library and was wondering if anyone knew how to apply the height above floor prompt to a base cabinet - I can't really work out how an upper cabinet gets drawn at that height..  I guess I'm asking where I can set the origin of the cabinet in the drawing. I know I could just draw it and move it to the desired height but I would like to know how to do this..

Thanks