To attend the festival you just need a pass or ticket to a film. An All-Access pass will get you access to every event in the festival, except the Filmmaker Brunch, and a VIP pass will get you into everything including the brunch.
You can also purchase tickets to single screenings if you don’t have a pass. Tickets to a single screening can only be purchased in person at the festival. Single screening tickets are $10 (with the exception of the 4K restoration of Lost Highway).