There are several ways to develop a case conceptualization of clients and their progress using the hexagon model.
ACT in Practice: Case Conceptualization in Acceptance and Commitment Therapy by Patty Bach and DJ Moran has a companion website that is hosted on the ACBS site, and provides a case conceptualization form freely available to you.
An external website also has an outline of a case formulation framework (based on the chapter in the Practical Guide to ACT) along with a form for therapists to use to complete the process (http://www.drluoma.com/actresources.html).
There are child pages below that provide several other ways of practicing developing a case conceptualization throughout therapy.