My best advice- confidence. Be confident in your content. You are the 'expert' for the day and you know your stuff. Remember to breathe, drink some water every couple of minutes, and take your time. If it helps, practice out loud to a friend or in front of a mirror. For me, practicing pre-loads the words into my brain and helps things flow more easily. And above all, you probably will stutter, stammer, or have a block. It happens to all of us. Your audience won't care as long as the information you're presenting is accurate and clearly laid out. You've got this! You're the expert explaining the details to everyone else. Good luck!