3 ideas
To make a present decision in a sequential situation, start from the final outcomes and reason backward, asking at each step what a rational player will do given what follows. By rolling back the chain of best responses, you determine your optimal first move based on how the game will actually play out, not how it begins.
A threat or promise only changes others' behavior if they believe you will actually carry it out, and belief often requires you to visibly destroy your own ability to back down. Burning bridges, signing binding contracts, or delegating to an inflexible agent makes a commitment credible precisely because it eliminates your freedom to act otherwise.
Rather than playing a fixed game well, skilled players alter the game itself before others act — using commitments, threats, and promises to change the payoffs others face. The first mover can shape the structure of incentives so that the rival's rational response leads to the outcome the mover wants.