The best advice is to get away from PowerPoint when you're starting to develop your presentation narrative. Do it in Word. Or Notepad. Or even in the notes area of PowerPoint. Just get away from thinking about the slides specifically.
I highly recommend Beyond Bullet Points to learn how to structure a presentation. I think this is the best resource for practical tips to plan your presentation. https://www.cliffatkinson.com/beyond-bullet-points and https://www.amazon.com/Beyond-Bullet-Points-PowerPoint-compelling/dp/150930553X/ref=sr_1_2?ie=UTF8&qid=1521471023&sr=8-2&keywords=beyond+bullet+points
Also, Everyday Business Storytelling: https://www.amazon.com/Everyday-Business-Storytelling-Simplify-Narrative/dp/1119704669/ref=sr_1_1?crid=W7PAG82LU1GD&dchild=1&keywords=everyday+business+storytelling&qid=1628870416&sprefix=everyday+busin%2Caps%2C210&sr=8-1