From concept to execution of the orders?
 

Operation NORVIC was an SOE operation with as target to interrupt railway communications near Remagen Germany. To be done by an agent dropped on the night of 20/21 march 1945 by parachute. Executing this drop was F/O Ferris and his crew on flight T9445 coded MA-O from the 161sq. out of Tempsford. They went missing and crashed near Lamormenil in Belgium and the whole crew was killed after they dropped the agent. I've done a some research on this but was wondering about the chain of command in the SOE.

My question is this:

Who comes up with the plans for an operations like NORVIC and how is it eventually formed into orders like the ones the F/O Ferris and his crew had received? So in short the whole timeline from concept to execution of the orders and by whom or what branch?