When you enable shopping cart feature (set Activate Shopping Cart config option to Yes), registrants can add multiple events into cart before processing registration for all of these selected events

If you use this feature, it will work much like a typical shopping cart. 

Sometime, you want to display registration form of an event inside a Joomla article. For this purpose, you can use Content - Events Booking Registration Form plugin (http://eventbookingdoc.joomservices.com/miscellaneous-plugins/content-registration-form). For example, below, we use that plugin to display registration form of event with ID = 154