This did not come with instructions, so I had to figure out how to use them from the photo on Amazon.  The bigger button is placed at the bottom and the smaller button is screwed to the top.  Place the watch with the glass facing down and the metal facing up.  The problem is that the screw to the top button sticks out a bit after the button is screwed on, so it made a bit of a dent to my watch's metal backing after the cover was pressed onto the watch.  It took quite a bit of pressing for the cover to finally click to the watch, thus there were moments when I was worried that the glass to the watch would crack.  However, it didn't crack and it worked after a while of pressing.  If the watch is with a closed metal band, it's not as easy to operate this press with the watch.  The press is best for watches with opened leather bands, but most leather band watches have easy to close thin covers that doesn't require a press.  So, the idea of using this press is a bit convoluted, but it does work with a bit of a dent to the watch.  You might not want to screw on the top button all the way, so not cause damage to your watch.