The guy will go through all your pre-screening questions first. You two will talk about them and that is the time where you could say that you stole a sota from the store you worked at as a teen then he will tell you "yes that counts or no that doesn't count." THEN when you answer the question for the "real deal" you can answer honestly. Also, the polograph guy writes up a report to send to your chief so if you say "yes" than the chief gets the full story and not just the yes. Might I suggest sitting down with your chief ahead of time and tell him about anything that might pop up? Usually they don't care (don't worry at all about that soda) but it makes the polygraph a lot easier if you're not worrying about what your chief is going to think. Most of the questions are designed just to tell them if you'll tell them the truth. Expect a lot of embarrassing sexual questions.
As for the part of the test when you're hooked up- no, you don't get to explain yourself. You answer yes or no- period. Don't worry though! You can get through this
