The question was " So what does 'Evacuate System' mean & why is that of any benefit, anyone knows?"
The video answered that question more than satisfactorily.
I saw no shaking of the cannister, I did see him turn the canister45/90 degrees.
There are some things in life that we have to leave to the experts and I believe this is one of them. You have to pay at some stage for everything in life or trying to do it cheap will cost you more in the long run.