How do I make full use of a generic 6-button mouse?

Solution 1:

You can use a tool like USB Overdrive to map various functions to the buttons on your generic 6-button mouse.

Solution 2:

yeah the button above or below the scroll is the adjustment of DPI of the mouse. mine is 4 types. if you click the 6th button then play on your cursor on the screen each click (6th button)you will notice the ranges how far can your cursor travel from left to right or up/down.