ACT works with six processes that together build "psychological flexibility": acceptance, defusion from thoughts, contact with the present moment, a broader sense of self, clarifying values and committed action. The names sound technical, but in practice they are very concrete.
In defusion, for example, you learn to see a thought like "I am useless" as just a thought, not an absolute truth. Therapists use metaphors, short mindfulness exercises and small experiences in session so these skills are felt, not only understood.
Then come values: what kind of parent, friend, colleague or person you want to be, and what small action this week could point in that direction.