Close well.
Tell them what you told them.
When you started you told them what you were going to tell them. Then, in your presentation, you tell them. When you are done, simply tell them what you told them.
Summarize your presentation by focusing on the most important points you made. People can usually remember three things. Tell them the three things you want them to take away. Then thank the audience and ask for questions. If you have closed well, any questions should come from the things you told them were important.
Remember, this is the “Show Business” part of the business world. The finale is a very important part of the show.