Mondays vs. monday

[mishy]

When do i add s to days, like Mondays, Tuesdays,etc.

[Tamara]

Hi

Classes are held on Mondays. (= every Monday)

Next Monday all classes are cancelled because of Bank Holiday.

You should spend some time on Sunday to be prepared for your Monday's class.

---
Correct me, please, if I made mistakes.
_________________
It’s impossible to learn swimming without entering the water…