Cols 73-80 were sometimes used for sequence numbers so when you spilled your cards on the floor you could run them through the sorting machine.

This may help you get the feel (pick the COBOL card at the top). [0]

For an even more authentic experience, write the program on a coding form first, then give it to an assistant for keypunching. [1]

[0] https://www.masswerk.at/keypunch/

[1] https://www.mainframestechhelp.com/tutorials/cobol/coding-sh...