Insert a card by clicking the slide at the top left of the card punch.
Click one of the numeric keys to punch the number (top left quarter of key).
Punching a letter was achieved by pressing down both the 10, 11 or 0 key as well as the key you wanted to enter. To do this with a mouse, click and hold down the 10,11 or 0 key for about a second and it will stay down, then click the letter you want. For example, for A (top right of key 1), hold 10 then press the 1; For K, hold 11 then press 2; for T, hold 0 then press 3.
REL releases the card, SKIP will jump to the next tab and SPACE just moves the card one step on without punching a hole.