Can't help with your 2nd question, unfortunately.
As for the 1st one, as far as I know, you don't attach the goods to follow (B4) form with the goods. You just have to show it to the Canadian customs when the goods arrive. The form always stays with you.
For example, if you've divided your goods to follow into two parts, and the first part arrived already, you go to get it and show your B4 form to the customs. Maybe they'll stamp it or something. Then when your second part arrives, you'll take that same form with you again.
I'm not completely sure about how some aspects of that work, like - what happens if you order a mail delivery to your house? The delivering company won't bring the customs officer to your door, obviously, so how do you show them your B4 form?
And another one - how do they check which of the declared goods you've brought in already, and which are still to be shipped?