In order to add events from different plays to a page of multiple events, follow these steps:
Click on the "Administration" tab and then click on "edit" under ''festival''.
Select from the dropdown menu the play you have set as the festival page:
Click on the "festival events" tab
Then click on "add events that wiil be shown at the festival".
On the pop-up window, select the events you want to be shown on this page and hit "save".