You can manage the KNX Push-button functions by going to going to Project Settings > KNX Push-button Functions. Edit existing functions with the edit button, or create new functions by clicking Add Function and filling in a name and a description.
To use a function (i.e. to be able to select the function from the drop down menu in the Device View) you first need to select/mark the function for the Devices that you want to use the KNX Push-button function.
You can do this in the device’s Device Setup page (see picture below). Open a device’s setup page by going to System > KNX Devices and clicking the edit button 
for the device you wish to edit. Then scroll down to Function Type and select the push-button functions you wish to use.
Tags: functions, knx functions, project settings, push-button
