If you have already purchased a drop in session through the membership tab and want to purchase another session before the same date of the next month you will need to purchase it here. This is because your original drop in subscription that gives you access to the booking calendar lasts for one month.

For example, if I purchased a drop in membership on the 15th of January and want to do another drop in session before the 15th of February I would purchase that session here and then sign up on the selecting sessions tab. If I then want to do another session after the 15th of February I would go to the membership tab and repurchase my drop in membership.