I have a small question. How do I set calendar to show the first day of the week is Monday.

Hi,

here the customization that you need to do.
edit /modules/mod_community_eventscalendar/calendar.js at line 84, change the code from

var dWeekDayOfMonthStart = new Date(dYear, dMonth, 1).getDay();

var dWeekDayOfMonthStart = new Date(dYear, dMonth, 0).getDay();

weekDays: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'],

weekDays: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'],

Hi.

In next release this will be possible without file hacking ;)