To confirm the trip booked by guests as a guide, you can check it at "Your bookings" or in the message thread.
You can check trip details at Tour information on "Your bookings". By checking that, you can see the details of the trip. Also, after the support guide is chosen, information of them will be displayed at "Your bookings".
If you have not found support guide yet, search for your support guide at "仲間から探す".