Flushes and kickers?

4 hearts on the board. One guy has a flush Ace high with a 4 of clubs kicker.

Another has king high flush with a queen of spades kicker.

Does it matter the high card of the flush, or does it go to the kicker?

Just the high card on the flush... And you can only use the best 5 card hand...

Suppose the Ace was community

Player 1: 3H 2H
Player 2: KH QH
Board: 4H 7H AH 9C JS

They both share the ace, but Player 2 has the next highest card.. The king. Therefore he wins.