I did a speech on my experiences learning snowboarding for one of my Toastmasters speech. The good thing about your topic is that it will allow you to use your hands and body a lot to demonstrate (which is why I chose my topic because the goal of the speech was to use effective gestures). It is better than standing up at the front of the room with your hands in your back pocket.
Watch your voice - make sure it's strong enough to be heard at the back of the room, and that you try to vary your pitch (e.g. not sounding monotone the whole way through). Maintain eye contact with people - look at one person and talk to them for 10 seconds, then find another person - move your eyes across the whole room (don't just look in one spot).
I would inject some of your personal experiences to liven it up - like what happened the first time you got up - if it was unsuccessful, what happened (ie. you drank a lot of water or got your arms ripped off), or how it felt. This is the "passion" that Bill is talking about. It makes it more personal and people can relate to your experiences.
If you are showing the video, don't put your back to the audience. Don't turn and talk to the screen - the audience can't hear when you do.
If you can, try to just have some index cards with your notes on it rather than reading a speech. Those notes should jog your memory as to what you wanted to talk about.
Organize your speech so you have an opening, the body and a conclusion. The opening should introduce the topic of your speech and get them interested in the subject ("grab their attention"). The body could contain the teaching components you described, then the conclusion should summarize what you spoke about and perhaps leave a course of action (what points do you want to leave them with?)
Above all, practise, practise, practise! The more times you practise, the more comfortable you will feel. Even video yourself so you can see how you come across.
Have fun! Public speaking is a challenge - I know how much I hated it in school.