What’s the Best Way to Write a Personal Development Plan?

I’ve just been assigned a personal development plan, and honestly, I’m completely lost on how to start. Like, how deep is too deep with personal reflection? Is this supposed to sound like an help with college assignment or more like I’m spilling my thoughts in a secret diary? I don’t know how to make something personal sound academic and structured (because I am stupid, maybe.) Plus, am I supposed to back my reflections with some kind of theory or just simply rely on my experiences? Seriously, if you’ve written one before, I could really use some advice on what’s the best way to approach it. Thank you.