Anytime you do stand-up training there are likely going to be a set of materials that you’ll be teaching from. It is important to be prepared and master the materials, but don’t be a slave to them.
If students ask questions that are covered later, answer the question briefly then get back on track. Never say, “we’ll get to that”. Pay attention to the flow of the day– the students may have better ideas that are more useful for “learning” than you do.
One example I had was when I was organizing training to City employees, the supervisor decided that a manager would get up and cover some specialized material that she was an expert in. She then called up another guy and they did an impromptu sketch instead of reading from the PowerPoint. It was unplanned and was the best thing that happened that day.