Save the pattern in your Photoshop directory in the goodies folder. That way, you always know where it is.
If you aren't comfortable doing this freehand, you can use an existing puzzle as a template by scanning it and then using the scan as a background to copy.
If you are having trouble with alignment, create a vertical grid from guides. Place the guides at 1-1/2 inch, 3 inches, and 4-1/2 inches. If the tabs are out of line, horizontal guides at ¾-inch, 2-1/4 inches, 3-3/4 inches, and 5-1/4 inches should mark the center of the tabs.