Scrabble blank tile - when drawing at beginning? stuck on tray at end?

I know how the blank tile is used DURING a game of Scrabble, but what if you draw one when determining who goes first at the beginning of the game? Is it better than getting an 'A'? Or do you draw again? Or if you're stuck with one on your tray at the end of the game, are you penalized any points? I don't see any rules about these two things anywhere in the rules, and am finding different players do it differently. Wondering if there are official rules about these. Please include link if there are.