check to see if it is enabled: 'View' > 'Today Pane' > select 'Show Today Pane' In the same place you will also see options you can select for prefered display:

• Show mini-Day
• show mini-month
• show none (removes the Date or calendar month display)

F11 key toggles the view of the 'Today Pane'

In Status Bar - Bottom right - you should see 'Today Pane' which you can click on to show or hide the 'Today Pane'

At the top of the 'Today Pane', above the Date, you will see: either 'Tasks, Events, or Events and Tasks' the arrows to the right of this can toggle through those options.

Additional Support Forum links that may of general help:

• https://support.mozilla.org/en-US/kb/lightning-user-interface
• https://support.mozilla.org/en-US/kb/creating-a-new-event-or-task
• https://support.mozilla.org/en-US/kb/creating-a-recurring-event
• https://support.mozilla.org/en-US/kb/inviting-other-people-events
• https://support.mozilla.org/en-US/kb/working-events
• https://support.mozilla.org/en-US/kb/changing-date-or-time-event

If you open the 'Calendar' in a tab You can choose to see eg: 'All Events'

Some images as guide below