At the top of the page there are four other buttons. Pressing one of them will select that section of the configuation interface. Pressing the selected button will focus that part of the configuration interface on the top node of that part of the interface.
It will probably make sense once you try it.
There are usually one or more buttons at the bottom of the page, to do things that does not fit nicely in the 'node with subnodes' methaphore, like adding a new virtual server, unfolding/folding more than one node at the time etc, at the top or bottom of the configuration interface.
Some buttons, like the 'add a new module' button are only available in certain nodes (a node of a certain type has been focused).