I don’t know if the below is of any help at all - I know a lot of it is easily said and much more difficult to apply.
All I would advise is to be as open minded as possible and try and keep in mind that your therapist will have no preconceptions about you whatsoever. Try and be as open as you can (I find this dreadfully difficult, still) with them and no matter how uneasy, embarrassed or ashamed you might feel talking about something, they are not sat there in judgement. Their job is to challenge your thought processes and help you try and recognise this.
It probably won’t be easy, I still come out of my sessions after a good five and a half years - might even be more now - of various therapies completely and utterly worn out. I often go off on tangents because by the time I need to finish one thought, another has usurped it and the original train of thought has long since gone.
Don’t worry if you’re stuck in a state of silence for a few minutes either whilst you wait for thoughts to arrange themselves, or indeed do spend much of the appointment in tears. Your therapist will be used to this and although it won’t necessarily make you feel any less awkward, try not to think of it as wasted time.
Even if you feel your first couple of sessions have been of no benefit, I would urge you to do all you can to persist. It can be a slow burn, but you may suddenly find a moment when a lightbulb goes on in your mind as you talk and something suddenly clicks into place (not that this will necessarily be a silver bullet curing all your problems, but a rare moment of clarity) and hopefully, at the end of the sessions you’ll be able to look back and see that you have made progress.
Also, there is an enormous degree of achievement in being able to haul yourself through a section of therapy when you’re feeling enormously vulnerable and fragile. The difficulty in going through that shouldn’t be understated or ignored.
If your sessions are anything like mine (I’m assuming you’re NHS?), and there’s a finite number of weeks, then don’t expect to come away with everything sorted and do try and do all you can to ensure there is still a pathway towards care once the sessions finished - whether through less regular reviews or referring for another block.
I wish you all the best with it and hope that you are able to find something useful to come out of them.