Reading the card
Here is a punch card, reading the word HELLO in binary.
01001000 01000101 01001100 01001100 01001111
Watch one spot on the card pass under the reader.
A hole means 1.
No hole means 0.
The machine does not see the word HELLO.
It only sees a line of yes-or-no marks, one position at a time.
After eight reads, those bits become one letter.