People often arrive at a first lesson expecting a test. It is not that, but it is not a chat either. The hour has a job to do: by the end of it I need to know what you can already do in English, what gets in your way, and what we should work on first.
What happens in the hour
We talk for the first twenty minutes or so. I ask about your work, your studies, what you read, and what you watch. The questions matter less than what happens while you answer them. I am listening for the gap between what you want to say and what you can say, because that gap is the thing lessons close.
Then we look at something written. That might be an email you have to send, a piece of an exam paper, or a short text I bring. Writing shows different problems from speaking: people who sound fluent sometimes write in a way that reads as abrupt, and people who hesitate when speaking often write well.
We finish by talking about what you want. A deadline changes everything. If your exam is in May, we work backwards from May. If you want to be able to hold your own in meetings, that is a different plan with a different pace.
What I am listening for
Three things, mostly.
Range. How many ways you have of saying the same thing. Learners often have one way, and it works until the situation shifts slightly.
Recovery. What you do when you do not know a word. Talking around a gap is a skill, and it is more useful than knowing the word would have been.
Patterns. Errors that repeat are worth fixing. Errors that happen once are usually just tiredness, and chasing them wastes your time.
What you get at the end
An honest assessment of your level, in plain terms rather than a label. A suggestion of what to work on first and why. And, if it applies, a realistic view of how long your goal will take.
Sometimes that last part is not what people want to hear. Moving from B1 to B2 is not a matter of weeks. Knowing that at the start is better than finding it out in April.
If you decide the plan is not for you, that is a reasonable outcome. You will at least leave with a clearer picture of where you stand.