What is the first thing you should ask before writing your presentation? What is the goal of the presentation? How long should the presentation be? Where can I find multimedia resources for the presentation? What is the most interesting way to start my presentation?

Answer: What is the goal of the presentation?

Explanation:

I would ask this first because the most important thing in your presentation is what your goal is and what you want to accomplish. Without knowing what your goal is, you will not be able to focus on the other things you mentioned.