Control new course of stream (6)
I believe the answer is:
master
'control new course' is the definition.
'master' can be an answer for 'control' (mastering is a kind of controlling). I am not certain of the 'new course' bit.
'of stream' is the wordplay.
'of' indicates anagramming the letters (the answer comes from or 'of' the letters).
'stream' with letters rearranged gives 'MASTER'.
Can you help me to learn more?
(Other definitions for master that I've seen before include "Schoolteacher" , "One in complete control; great artist" , "Skilled practitioner" , "Strong chess player" , "Main; overcome; original recording" .)