Customizing Portal page

Customizing Portal page

Hi,

As we have a lot of events, the custom domain is really usefull to see all current & future events. Our events are limied to 12 people. However I've a request to display events that have still tickets (ie, less that 12 people bought the tickets). This is a view for the visitors.

How can I customized the page and how can I filter events to show only events with tickets to be sold ?

Regards