How can I get inside the Old Mint?

Hint 1 of 10:

This is a "classic" square puzzle.

Hint 2 of 10:

The object is to have every row and column (top to bottom; left to right; and
diagonal) add up to the same number.

Hint 3 of 10:

This puzzle is a "Mason" square.

Hint 4 of 10:

The number is NOT 13, even though all of the clues mention that number.

Hint 5 of 10:

Instead, use a number important to the Masons.

Hint 6 of 10:

The magic number is 15.

Hint 7 of 10:

You can only use each number once.

Hint 8 of 10:

Move the squares until each row adds up to the number 15.

Hint 9 of 10:

Diagonally from top left to bottom right, the numbers are: 4, 5 and 6

Hint 10 of 10:

The top row numbers are: 4, 9 and 2