Advanced Tactics is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

When this enchantment enters, create a 5x5 grid for as long as it remains on the battlefield. Starting with the top left space and skipping every other space, choose a random creature and put it in the grid. As a creature enters, its controller puts it in an empty space. Creatures can't block creatures they aren't orthogonally adjacent to. : Move target creature you control one space left, right, up, or down. Any player may activate this ability.