Every individual added to the Events Calendar is placed into a Calendar Group. Events you add are added on behalf of that Group. Calendar Group members may have more than one Group assignment.
When you log into the Events Calendar, you'll be placed into your default Calendar Group, and see a list of all its associated events. You can see your default Calendar Group referenced next to the Toolbox at the top of the screen.
If you are in other Calendar Groups, you will need to switch into the other Group to add events on its behalf. From the drop-down menu next to the Toolbox, select the appropriate Group.
The associated event listing will change to that of the newly chosen Calendar Group.