Calendar - Go to top right corner of page besides your profile icon you can see Calendar icon now at calendar page click on any date or time frame, at this modal window enter Event Title, Description, Event Date, Event Colour and Event Type (Public is visible to all, Private is only you can see this event, All <your role> is this event will be visible to all users of your role, Protected that means it is visible to all staff members but not patient) then click on Save button.

You can check created event at Calendar on created date box.