You can share the event with your guests via Facebook & Twitter or by adding a ticket widget to your website.
Find your event in "My events" at the top panel. You can then find this option under "Manage" button on your selected event. Navigate to the left-hand sidebar and select "Marketing" then "Share Event" option.
To share the event through social media you click on the Facebook or Twitter button, and the event will appear on your timeline.
If you want to add a ticket widget to your website click on the "ticket widget" button and copy the embed code to insert on your website. If this sounds confusing, you might want to ask your site administrator to give you a hand.