Most lists in Event Temple that have a checkbox will allow you to batch select, and then make an update. Depending on where you are the actions will vary
Open the Page you wish to perform Batch Actions on (Bookings, Events, Documents or Tasks) or Open the various Tabs of a Booking (Events on the Summary Subtab, Task Tab, Line Items Tab, Documents Tab)
Select the checkbox at the top of the list or check the boxes next to the items you wish to edit
Click the Batch Actions
Select the action you want to perform. Depending on where you are the available actions will vary
Click the Apply button
Batch Action examples:
Batch Actions for Contacts or Accounts or Invoices are not available