How can I see what bookings a customer has made?

Bookings made, can be found in several places. They are displayed on the customer's dashboard in the 'Booking filter results' block. In the booking overview (filter) you can also search for bookings for a particular customer. Adding the search field 'customer ID' or 'surname' to the filter will reveal the bookings that are linked to this specific customer.

How can i see what bookings a customer has made in the past?

It is possible to create a search filter with a relative date that searches for past bookings. When you include an additional block 'Filter bookings' on the customer dashboard, you can link the saved filter to this block. The result is that this block displays the customers past bookings. You could, for example, do the same for bookings that have been cancelled. To clearly differentiate between the blocks, you could give them a different colour.