The first thing you should do is research. Read and learn about kangaroos, and then write down the facts you find interesting and where you found these facts (the website address, or the name and author of a book). From there, you can figure out the one or few things you want to focus your presentation on. It could be on the day-in-the-life of a kangaroo, or what they eat, where they live, how they interact with each other, what makes them unique from other animals, and so on. One particular thing that's interesting with kangaroos is how they have babies, and I recommend researching that for a starting point. This will help by having a kangaroo model, because you can show what newborn kangaroos do that is unique and how they grow.

I would recommend having these things:
- a poster board to hold all your key information, photos, and diagrams, as well as the title of your presentation and your name.
- notecards for yourself with all the information that you want to share with the class. This will make you less nervous and make it easier to remember what to say next.
- your model. Which I'm not sure if you need to draw one or make one. Drawing one would be easier because you could show how the kangaroo pouch works and the stages of a newborn kangaroo.

Hope that helps, good luck!