The Veterans Health Administration, part of the US Department of Veterans Affairs, has a video series about ACT that provides an introduction to the six core processes of ACT.
An introduction to acceptance in Acceptance and Commitment Therapy (ACT).
Acceptance means letting go of struggling with thoughts, feelings, and circumstances when doing so gets in the way of building a meaningful life.
Willingness is another word for acceptance. Being willing means opening up to all thoughts and feelings, whether painful or pleasant, when doing so takes you in the direction of building a meaningful life.
Defusion means becoming aware of the process of thinking and undermining any unnecessary influence of thoughts on behavior.
The observing self, or "self-as-context," is a safe and stable perspective from which all experiences can be viewed. It is a self which is distinct from thoughts and feelings. Thoughts and feelings are transient; the observing self is always there.
Contacted with the present moment, or simply "presence," means bringing flexible attention to experience as it unfolds continuously in the present.
Values are personally chosen, global qualities of ongoing action. Examples of values include "being loving and compassionate," "maintaining health and fitness," and "taking care of my family." Committed Actions are any actions, big or small, in the service of values.