The Button Bar is a way for users to quickly access certain features of the program using a single mouse click. Most of the functions (and all of the major ones) found on the menu bar have a corresponding speed button. If the user hovers over the particular button a small yellow box appears which indicates the function of that button.
All of these functions are explained at the appropriate location in this help file.
Reading left to right on the Bar, the buttons are:
Create New Artist/Title Window
Create New Artist/Cat # Window
Filter the Data (Boolean Search)
Open Help File (This document)