How do I create a week commencing calendar?

I'd like to create a very simple calendar that allows me to click a next button, and it will display the next monday.

So for this month, for example, it will display:

Week commencing 23 Aug 21.

I then click the next button, and it changes to:

Week commencing 30 Aug 21.

I could do this with a lot of effort using the old browser timestamp system, but I was wondering it it was easy to do with the newer Date object.

I had a look at the Scirra examples, but rather than use the date object to create a calendar, they opted to provide an example for a calculator.