If statements using time and conditions

The employee should start at 08:00 If he is late by more than 3mins and less than 20mins then the answer must be "-1" If late by more than 20mins and less than 40mins then the answer must be "-3" If late by more than 40mins and less than 60mins then the answer must be "-5" If late by more than 60mins than "-10" else if early then the answer must read "ok"

Please can you assist.