Usually it goes something like this:
Student: "Am I doing it right?"
Me: "Let's work on it together."
Most of us unconsciously move our arms when we speak. There's not too much rhyme or reason to what we're doing. It can be a bit of "danger-danger-Will-Robinson" at times. Being conscious of our gestures can propel our speech-making to a professional level. Use your gestures to describe. Take the opportunity to illustrate your points:
"The conversion rate has shrunk over the past few months."
"He cradled that kitten like a baby."
"Let's join forces to defeat The Empire."
"The bird swooped down and grazed my head."
"We're going to expand our European presence next year."
You get the idea. For any of these you likely could easily figure out what an appropriate gesture would be that would add color and excitement to your words.
As you rehearse your presentation think about which of your adjectives and verbs should be brought to life by adding a meaningful gesture. You don't have to (or want to) use a gesture at every possible opportunity; you're not trying to act out your speech. The goal is to gesture when you want to add a little flavor, grab attention, give your story more impact or make it (and you) more memorable.
Once you figure out what you're going to do, rehearse these gestures along with your presentation! I cannot stress this enough. The gestures may feel awkward at first but I assure you, with practice they will flow naturally and genuinely. It's a skill that will improve your confidence as well as your speech-making prowess.