The best opening move for 6-6 in backgammon is 24/18(2) 13/7(2). Both bar points. Watch it on the board, then read the idea behind it.
The idea behind the move
With 6-6 play 24/18(2) 13/7(2): both back checkers move to the 18-point and make a point, and two checkers from the 13-point make the bar point. You get two points in one move.
What comes next
Your back checkers are already free, and the bar point in front of your home board blocks your opponent. On ZAR the first roll can be a double; in tournaments a double does not start the game.
How to read the move
A move like 24/18 means one checker goes from your 24-point to your 18-point. Points are counted from your side: 24 is the farthest, 1 is the deepest in your home board. “(2)” after a move means you play it with two checkers.