The board in question is a single board, 4-axis, with fixed output connections. The step and dir signals to x,y,z,a axis are wired internally, and cannot be changed. The 6560 driver has been superseded by the TB6600 driver. The 6560 had problems, and is now obsolete. The best option, in my opinion, is try to return the board to the seller, and replace with the 6600 version, with the later voltage regulators. The later board has better voltage regulators for the 5v, and 10v output signals, which do not overheat. This board design has undergone about 3 or 4 redesigns, and the latest version has a heat sink for the drivers which covers the entire base, has eliminated the fan, and is a USB input from the computer. It is perhaps the most compact 4-axis board system made for a small to mid motor system. Sorry to sound negative about the 6560, but it is not worth your time to try to fix an old, problematic design, that has evolved with better hardware components.
John