Conversion from non-native to native English

Thank you for the 3 corrections this time.

Mister Micawber I understood that the employee worked on Saturday!

No, no, the incident happened on Saturday. I understand that even if it was a case that the worker worked on 'Saturday(s)' only, we could have used either of the phrases - ...on Saturday; on Saturdays.

e.g. I ask questions on EnglishForward on Saturday/Saturdays.