Look for ads in a newspaper, magazine, flier, or notice board. You must reach the venue to audition according to the details given in the advertisement. You are then given a script that you can rehearse for about 10 minutes. Post that you have to be facing the camera in a movie setting with the required lights, etc., and you are supposed to say the rehearsed lines with acting and drama put into them. That's how you audition, and then when you are home in a few days you get a call if you've done well at your audition.