The Quick Instrumentation Buttons are designed to allow you to enter a single instrumentation over and over again. This is useful in the following cases:

• A pops gig where all the charts have the same arranger
• A movie score where all cues have the same instrumentation

The buttons are located as follows in the File Naming view.

You can set the instrumentation these buttons call up by navigating to Settings > Instrumentation. See here for more details.