Fundamental Knowledge for M.Tech Power Electronics

Sir/madam, Could you please help in basics of engineering as i completed my B.Tech in INSTRUMENTATION stream 2008 with 55%. Now after 6 years i have joined M.Tech in POWER ELECTRONICS in management quota has it been 6 years.. I forgot all engineering knowledge. Kindly help me to cope up with basics so that I will not face issue in M.Tech I still have 20 days time to go to college.