adding event sources section

Author: OlivierJourdan

www/en/modules/ROOT/images/03-event-sources-ui-fp.png

@@ -1,4 +1,35 @@
 = Event Sources
 :page-toclevels: 1
 
-== User Interface
+== User Interface
+
+The first source of events, you come across when starting with {lv} are the events generated by the UI when a user of your application use the mouse or the keybard.
+
+Example code: 01a - Event Sources - User Interface.vi
+
+.Front Panel
+image::03-event-sources-ui-fp.png[]
+
+.Diagram
+image::04-event-sources-ui-dg.png[]
+
+== User Events a.k.a Custom Events
+
+The User Events are probably the worst named {lv} feature.
+Behind this name, you'll find the way to create and generate events programatically
+
+NOTE: This source of events is the corner stones of many event driven architectures. The https://www.dqmh.org[DQMH framework] is probably one of the most popular framework based on the {lv} user event feature.
+
+Example code: 01b - Event Sources - Custom Events.vi
+
+.Front Panel
+image::05-event-sources-user-event-fp.png.png[]
+
+.Diagram
+image::06-event-sources-user-event-dg.png.png[]
+
+== Callback
+
+== Daqmx
+
+IMPORTANT: This example requieres the NI Daqmx driver to be executed.