Use edge of the pick??

I really don´t know what " use edge of the pick" means . can you show me picture of that or something? I want to learn to play Metallica - Ones solo :) .

Hard to tell without knowing the context that the sentence was used in.
Edge can either mean the pointy end of the triangle, or the side of the pick.
ie, if it says, 'scrape down the strings with the edge of the pick' it probably means the side of the pick.

About metallica's one solo; you should try holding further down on the pick and to hit the strings with just the tip of the pick, and try tilting the pick downwards a bit so it's not completely horizontal, it's usually easier to play fast lead solo's like that. good luck. ;)