You are laying plastic down before the flooring, yes? When we did our floors we started from the corner, that was farther from the entry area. Use a reverse saw blade for cutting. Also take 1-2 pcs of flooring and cut them in 1/2. use one of them as the starter. Remember laminate / floating floors do not get pushed up against the wall. IIRC you are given spacers [ 1/4"] to use between laminate and wall.
No you do not. Start from any corner