Instantiating Custom Symbols

I have used LTspice for awhile and am still trying to figure out Qspice, and which commands/file conventions have been preserved. In LTspice, I would create a schematic and associated symbol for a subcircuit, and then I would be able to instantiate my custom symbol in a new schematic created in the same folder where the symbol and its schematic were saved. I am having difficulty figuring out how to create a subcircuit and associated symbol, and then instantiate my symbol in a new schematic. Can anyone help with this?