Question

When do you use "Then" and when do you use "Than"?

Answer 1

"Then" is used in an "if-then" scenario, to dictate chronological order. In other words, "If you jump off, then you will fall," or "he was attacked and then retreated."
"Than" is used for comparisons. In other words, "The egg was bigger than the pea," or "I'm stronger than you."

Answer 2

Normally than is comparing something like this "Steve wanted a red shirt rather than a blue shirt." "i like swimming every now and then" "he said it then why wouldn't he say it now?" "i would rather eat fish than frog." <span />