When I started with therapy it was for one purpose, I needed help with unlearning a lifetime of unhealthy ways of dealing with being trans and help dealing with the tons of emotional baggage, especially my oldest and dearest friends, Shame & Guilt. The direct Trans and transitioning wasn't even on the agenda. After 2 utter fail transition experiments in my early life, any sort of transition was off the radar.
First sessions are generally "Getting to know you", medical history, psycho-social history/needs background stuff, generally one sided and touching on "Why are you here?". Second sessions more getting into the meat.
How the sessions actually go depends on your "Goals" (spoken and unspoken) and also depend on the therapist experience. My first therapist was a generalist, out in a rural area, whose major trans experience came via dealing with several of my support group members. A lot of his education on trans issues came via these same people. After several years there I got to move back to the NYC metro area where I had access to for real experienced gender therapists. There is a difference. I strongly suspect a trans gender therapist has to be even better. But then, there is also loosing the detached objectivity risk. My TG Support group is enough of a cheering squad with the many members answer to life is often "F what others think, do what you want" as the pathway to Nirvana.