Switching from phone banking career to mechanical engineering

Dear Engineers,

Graduated in 2014 still confused what to do presently working as a phone banking officer which I want to resign as early as possible

SO I request you all give me a feedback what to do next I don't remember my academics too

I just have degree that's it and I need suggestion what should I do to get immediate job in mechanical engineering stream

what skills I have to develop?
which courses I have to do?
Which field I have to select for getting in industry

Please share your suggestion and advice