I can't wrap my mind around lesson plans - help? studying to be a teacher

Okay, so please don't judge, but lesson plans aren't clicking for me. I have an assignment to do a full lesson plan, and though I have filled out a bit - it makes no sense to me. I'm having difficulties visualizing how it could play out for some reason. I have only done 30 hours in an actual classroom, and during that time, I didn't really know about lesson plans. Am I overcomplicating it? Overthinking it? Any advice as to how to write one? I've been scouring for help on the internet. I just thought I'd come here for possibly more help or clarity. Thanks.