Can I Get Some Advice For Testifying Against A Guy I Caught Masturbating At A Park?

I 22f am a very anxious person. I’ve always been awful at public speaking. However, I’m very adamant on helping get this guy the consequences that he deserves. Can someone give me a rundown of how this might go? What questions should I practice answering?

For context, this is the trial. 3 months ago my boyfriend and I were in a hammock at a park when a guy came and sat at a pavilion. We found it odd how close he was sitting to us considering the various other places to sit at the park. Anyway, after a couple hours we noticed his pants were at his ankles and he was masturbating while watching his phone. He suddenly stood up to face us and came on the ground. I caught all of this on video and took it to police immediately. There were also kids running 30ish yards away who thankfully didn’t see him. But his intents were obvious for coming to a park to masturbate.