The servo connectors are the usual that you plug into the RC receiver and probably the flight controller (depending on model)
as in photo below, you will only need two wires though, miss out the centre
The fourth Strobon just wires in parallel with the 3 shown.
If you have 4, all sync’d together then the quick pulse flashes, 4 at the same time, may momentarily overload a 2A sBEC. just try it and see if it is OK, no harm will come of it…
If you did not sync them then the randomly timed flashes would not be a problem
Cheers
Steve 
