Writing new block or editing existing block in Gnuradio Companion Windows

Greetings everyone,
My sincere apologies in advance if this question has been asked before,

  1. Is there any tutorial on how to write a new block in GRC windows OS?
    Those I searched are in linux OS.2) Or tutorial available on how to edit
    existing block in GRC?
    I am looking at modifying the costas loop block output constellation for
    I am using GRC 3.6.4 on Win7.
    Thank you very much.

Hi Sun,

GNU Radio does not really care about your OS; unless you want to do
something OS-specific, the source code is all the same.

Also, 3.6.4 is obsolete; update to 3.7.4 if possible.