Opening and Closing the Lid
During the compression cycle, it is absolutely essential that the lid be completely closed and locked, otherwise the extreme pressure of the jack can (and will) damage the block press. The photo below shows the lid in the unlocked position.

Lid in the UNLOCKED position

Get a feel for how the lid operates BEFORE attempting to make your first block. First open it, then close it completely and LOCK it as shown below.

Lid in the fully closed and LOCKED position

Lid in the fully closed and LOCKED position, from the back side of the block press