Here here will find a series of tutorials that will enable the use of HostDesigner and auxilliary tools.
Making molecular mechanics (MM) input files
Running MM conformational analysis
Evaluating ligand structures with MM
These exercises were created Supramolecular Design Institute and edited for this site by @drmperez.
The HostDesigner code can be found at:
https://sourceforge.net/projects/hostdesigner/
HostDesigner download contains the stand alone codes:
The PCModel program can be downloaded from:
http://www.serenasoft.com/license.html