The focus of the first session or two is for the therapist to learn more about the relationship. The couple's therapist must understand what's going on and what brought the couple into therapy in the first place. It's important to understand then what the issues are and what is the history of those issues such as addictions, affairs, abuse, communication or intimacy struggles. Each partner is asked to give their own perspective. Sometimes the couple may agree and sometimes they don't. A couple's therapist is not there to judge who is right or wrong but to gain more understanding of the patterns that the couples get into when they are trying to communicate or solve the problem, and how they become stuck in those patterns that are not working for them.
It's also important for the couple's therapist to know more about each person's individual histories like what did you experience as a kid? What was it like growing up in your home? Who did you go to as a child for support and comfort? This helps the therapist understand what you may learned a child that you bring into your adult relationship that may work well or not.
What are the strengths in the relationship? Have you ever felt safe or secure, heard or understood in your relationship? This is at times difficult for couples to imagine because they are feeling so much distress and negative emotion. It tends to color how each partner views the relationship as a whole, and the memories (even the good ones). But knowing what is or was good in your relationship helps the couple and the couple's therapist know the direction or goals of therapy.
Couples therapy does take some time, patience, tolerance of being uncomfortable at times, and a lot of work for both partners. The outcome of couples therapy is less successful when either partner is not willing to do the work in or out of the session, or when the expection is that the therapist will fix or solve all the problems of the relationship. A couple's therapist is to help the couple gain understanding of the pattern that they struggle to get out of, and guide/coach the couple in the right direction to find safety, security and connection in the relationship.
You may also want to read, How to get the Most Out of Couples Therapy.