If your studio shares recordings, they are in the Videos tab and you can watch them any time.
Sign in and open Videos from the menu. If you do not see it, your studio has not turned on its online library.
Tap any card to open it. The length is shown on the thumbnail.
The video plays on the page. Anything the instructor wants you to know — what to bring, how to modify a pose — is in the description under the player.