I have tried searching for the difference between postgraduate certificate and diploma but I have not gotten any clarification. I will love to know their major difference(s) with regards to how they can aid my admission for Masters.
Let me put it like this, I've secure a Postgraduate Certificate offer ( from a college in Canada ) but i do not know if after completion this would lead to straight Master or I will still have to take a diploma course before my master program.

Another funny question is, What is the Education Degree hierarchy like, I mean like after Bsc, Msc,, what next and next?

Post graduate certificate/Pgd is same thing. i.e the 'post' means after graduating with nce,hnd or bsc.
Now after bsc/hnd or Pgd is Msc or Mba. After msc/MBA is Dba/phd. After phd/dba u can becom a prof meeting the requirements to be regarded as one

Thanks so much, u mean i can use graduate certificate to gain admission for a masters?