Start with choosing your way of commuting as a rider. Then select your start & end location, set I'll share a ride mode on, and then set your ride. You'll see the driver ride mates on the same route with you.
Add the ones you'd like to "Your ride list". Then you'll auto-match with the ride mates from your ride list. Once you match with a ride mate you can text to them for the trip details. You can cancel the ride after you match.
If you do not want to share a ride you can cancel your trip or set "Just browsing" mode on so that no one will see you.