Do you have the manual? The series of button presses required to make it look for the marks is very non-intuitive.
When loading the vinyl make sure it is straight and the outermost pinch rollers are outside the corner marks. When the machine is done checking the vinyl, the display should read TP1. If it doesn't, make sure you've turned on the function. If you've done something else and it doesn't say TP1, pressing the END key will bring back TP1.
Use the arrow keys to put the red light in the first corner mark. Then press ENTER. It will read the marks.
When it finishes reading the marks you have to press ENTER 3 times to review the measurements. Then you press REMOTE to enable sending the cut commands from the computer.
