Can I start the week on Monday?

Yes, in the Fixed Week layout, which lines up weekdays in columns across every month. Open the calendar menu and choose Display Options. Under Layout, select Fixed Week, then set Week starts on to Monday. The Week starts on setting appears only while Fixed Week is selected.

Fixed Week is a Premium feature. The default Date Grid layout starts each month on the 1st, so it has no week start to change. Week numbers follow the ISO standard, where weeks start on Monday. Display options are set per calendar, and only the calendar owner can change them.