Anti-Stick Strip……

[Unregistered-Dodgeman]

The plastic strip (they used to be paper) is to keep the tar from one shingle from sticking to the next shingle while they are in the bundle. It doesn’t hurt to remove them, but it isn’t necessary.
As to instructions, the back of the bundles have good instructions on them, or you might try visiting the manufacturers websites.
Good Luck!
Dodgeman