Yes, you can! You are able to have up to 6 outstanding bookings at any time (4 standing bookings if you have the "Lite" membership). Once you have checked in to a class you are immediately able to book another. Alternatively, you can cancel an upcoming booking if something more appealing pops up! Or you can book an Additional Workout.
You are able to view and book classes 2 weeks out. You can view your upcoming bookings either through the app or the website, and can cancel them from either as well. Remember that you can visit each location 2-4 times per 30 day period depending on your membership.
Not sure where you stand on the number of visits to a certain location? You can monitor this via "Account > Workouts > Visits this period" in the app. Past, future and missed reservations count towards this number so keep that in mind!
Note: A booking in the future also counts as one of the visits. An open training visit also counts as one visit.