Hi Richard,
Thanks for reaching out! Event Tickets Plus, when paired with WooCommerce for payment processing and order management, uses Woo’s shopping cart functionality for handling tickets. This means that your users can easily move between events and add multiple tickets to their cart before completing a purchase, and there’s no need to add on any additional plugins to make it happen! You can see a simple demonstration of the cart and purchase flow for Event Tickets Plus on our WP Shindig demo site:
http://wpshindig.com/event/events-tickets-demo/
If you’re using The Events Calendar and/or Events Calendar PRO to power your calendar events, simply add on Event Tickets for basic ticketing support and Event Tickets Plus for paid tickets, and you should be all set! 🙂
I hope that helps! Thanks again, and let me know if you should have any other questions!