Mark the location you want to install the lock on with a pencil. Make sure the marks correspond so the lock can slide easily.
Drill a hole measuring 1/2-inch in the marked area.
Slide the lock cylinder from the outside of the door. Screw it in place with the bolt chamber from behind the door, ensuring that the bolt extends behind the other door, using screws that come with the lock mechanism.
Cut a hole out of the wood block wide enough to fit the bolt tightly. For a circular bolt, use an electric drill bit. If your bolt is slightly rounded, you may need a jigsaw. If your bolt is square, use a circular saw with a diameter slightly smaller than the hole you intend to make. As the depth of this hole may be deeper than what you can reach with a standard saw, the small size of a jigsaw blade makes it a decent solution to cut out the rest of the hole.
Screw the block on the back of the other door using a 3/4-inch screw in each corner of the block. Lock the cabinet and gently pull on the doors to test it and make sure the bolt slides comfortably into the hole you cut.