What is Process for perparing PGT(Post Graduate Teacher) Examination and at which period the Exam starts ?

My wife have done B.A(1st Class) , B.Ed(1st class) and M.A(English)(1st Class), and she has an Two and half year expierence in teaching Line.Now I have heard abt the PGT(Post Graduate test), and she want attend that Exam. Can you pls tell the procedure and period when this exam held for this year.