Adding button to the toolbar
For the people that can't find the buttons...
A number of my extensions contain toolbar buttons. They are located in the Customize Toolbar window. There are two ways to get there. The first to to right click on the toolbar (click with the right mouse button) and press Customize.
The second to to go to the View menu, then the Toolbars submenu and click Customize.
In the window that opens up, find a button that you want to use and click and hold the mouse button on it, and drag it onto the toolbar at the desired location. As you can see below, with the History button.
In the same way you can drag button off the toolbar, or even between them.