On/Off: turn on and off
Configure: configure the driver know that the devices capabilities are
Refresh: refresh the switch's current states
Flash: flash the switch state (on/off) until turned off
Push/Hold/Release: button controller functions that use the on/off positions as a button
Configure is a button that sends or resends the device commands that make the device match the driver expectations. This is usually clicked when you change drivers. Let's imagine that it first joined as a generic ZWave dimmer. That process does a configure and sets the device with the parameters the hub is expecting. Because the generic driver isn't device specific, it has a smaller subset of expectations. Then you change the driver to the GE Enbrighten Smart Dimmer. The device and the driver now don't exactly match. Clicking Configure might, for example, query the device and find it supports Scene and then ask how many buttons the device has. At the end of the process the driver and the device are aligned on both features and the default (now) values.