Show the Full Ribbon
When you open a new notebook, the ribbon might be collapsed.
This is a great way of increasing the size of the user input pane, but it does not show you all groups and options within the ribbon.
You can only see the ribbon tab headings, and you only see the ribbon groups when you click on a particular tab.
Click on any tab in the ribbon headings and the full ribbon will appear.
Right click anywhere on the full ribbon and choose Collapse the Ribbon. This acts as a toggle to collapse or show the full ribbon.
There is also a useful Show Ribbon setting toggle so you can set the ribbon to always show.
Click on the small down chevron icon on the very right of the ribbon and set this to Always show Ribbon.