Define subcircuit in Virtuoso Schematic using SPICE

Hi,
I'm using Affirma Virtuoso Schematic Editor to design the circuit
and later simulate using Spectre.
The question is that I want to put a subcircuit( an OpAmp), which is
defined in SPICE description from manufacturer. What instance should I
use in schematic and where should I put the text description? Is there
any other concern when using Spectre?
I really appreciate your help.

Lawrence