Electronic advice needed to setup Arduino Uno for highspeed photography

Now here is the complete schematic

Sorry but this is not a schematic, it is a physical layout diagram and is almost imposable to read t see what circuit you have. A schematic has proper electronic symbols and does not show the physical layout just the electrical connections.

see:- http://blog.makezine.com/archive/2011/01/reading-circuit-diagrams.html

In the schematic you can see an orange wire (Volt), how should I connect this wire?

Assuming this is the emitter of the transistor then connect it to -pol