The Interpolation Slider Wizard is a script that allows you to create slider widgets which can be used to pose a rig or any part of a rig. All it needs you to do is provided it with a few keyposes, and it will generate a Master Controller which will allow you to apply one of these poses, or an intermediary between two of these poses, to your character.
For example, you can start by creating a front, 3/4 front, side, 3/4 back and back poses for your character. Then, you can use the Interpolation Slider Wizard to generate a slider widget based on these poses, and you will have a slider widget that can instantly make your character face any angle.
To complete this topic, you will need the following from the sample material you downloaded:
The Interpolation Slider Wizard is very simple to use. All it needs is for you to create your keyposes, feed them to it and it will generate a fully functional slider widget, without any need for scripting.