Confession is a wonderful thing.
When you enter the confessional, you can make the sign of the cross (the priest might make it with you). Then I say “Bless me Father, for I have sinned, it’s been [however long] since my last confession.” “Since then, I’ve robbed a bank, missed Mass 3 times, and gossiped.” When you reach the end of your list, you can say “I am sorry for these and all my sins.” That lets the priest know that you are done.
Say your most serious sins first. Get that over with. Last time, I had drew a blank, and after a few seconds of me trying to remember, Father picked up the slack.
Listen to what the priest has to say. He will probably ask you to say an Act of Contrition. If you have one memorized, that is fine. Otherwise you can make up our own. Then he will give you absolution. Make the sign of the cross, tell him “thank you” and hopefully, you will walk out feeling like a weight has been lifted from your shoulders.
I don’t tend to dialogue too much. If I have a specific question, I will ask it, but generally I just state the facts and my priest doesn’t tend to give much advice unless I ask. Some priests will. Listen as if that’s Jesus speaking to you.
I wouldn’t justify the reasons why I committed my sins. You sinned. You offended God, who loves you more than anything. Don’t try to rationalize it, unless you think it really makes a difference - ex; “I robbed a bank because I needed money to feed my 8 kids who hadn’t eaten in 3 days. or I robbed a bank to support my crack addiction.”
I tend to generalize. The priest can always ask questions if he needs more information.
I like to go face to face, but that is purely a personal preference. Many people prefer the anonymity of the screen.