Simply enter your origin and destination, date and time of travel, plan by departure or arrival time, then hit "Get Directions". You'll be redirected to the Google Maps page with the result. If you are happy with this result, you are all set!
Click on "Schedule Explorer" on the left side of the screen within the Google Maps page. Scroll up or down for more alternatives. You can also change your date and time of travel, and explore other travel options such as best route, fewer transfers and less walking on this screen.
Select the preferred trip plan in "Schedule Explorer" for additional details about that trip.