Firstly - welcome to the forums Mike hope you enjoy the place. This is as good a spot as any for your question.
Obviously you have a particular sin or sins that you’re worried about confessing. Rest assured that priests honestly do pretty much hear it all in the confessional, so please don’t be scared to go into just a little detail about your sins. It really does help them in knowing how best to advise you, if you need advice.
You know that there are grades of sin. If you were just to say ‘I broke the seventh commandment’ or even just ‘I stole something’ … well, that would could mean that stealing five dollars from your mom’s spare change jar or could equally mean that you held up a bank and got away with a few million. There’s a big difference between the types of sin covered by that one commandment, so you need to be just a little more detailed!!!
Doesn’t mean you need to give every last detail either. Just saying ‘I stole five bucks from my mom’s change jar’ or ‘I held up a bank and stole x million dollars’ should be about the right level - if the priest needs more detail he’ll ask questions about it.
And yes, if possible you should say how many times or how often (perhaps just make an educated guess) you committed a particular sin. If you honestly don’t know, say so. This helps the priest in knowing if a particular sin is a real problem for you.
If you find yourself literally having difficulty speaking from nerves or for any other reason then certainly you could probably tell the priest so and have him read a written list.
And if you want to make a list and read from it yourself that’s absolutely fine. In fact it’s a great idea and something a lot of people do (yours truly included). You can even enjoy shredding it or burning it afterwards as a reminder that your sins are all forgiven and forgotten in confession.
But even if you do forget something, remember that it’s forgiven anyway as long as you honestly have simply forgotten.