You shall see calendar displaying the current month. On your right you will find a small calendar with the different months and to the right you will have the ToDos list.
By clicking on a square corresponding to a date ans time , you can add a new event, name your event and location.
In the top bar, you can create a new event by clicking on the appropriate button and you can view your calendar by "Day", "Week", "Month", "Year" or as a "List":
You can create multiple calendars, by clickin on the small gear button > Create Calendar
You can add a task by clicking on the small " + " button, located in the ToDos section
The "Actions" button allows you to Share a calendar, add holidays , add a friend's calendar etc...