Yes, it needs the windows platform to run on. Let me know if you need some time to try to install windows on your Mac (or find an old windows machine) or if you would like a refund for this new order. I can refund up to 30 days from the order.

I use VMWare Fusion for Windows on my Mac. ESPlanner has been working great for years for me with that setup.

To clarify, besides VMWare Fusion or Parallels, you'll need an installable copy of Windows 10 (or 7), and an installable copy of MS Excel for Windows.

You don't need to buy Fusion or Parallels because the Mac OS can boot into Bootcamp which is a Windows emulation program that's part of the Mac OS. Here's info on Bootcamp. You will still need a copy of Windows 7, 8 or 10 and a Windows version of Microsoft Excel.
https://support.apple.com/boot-camp
James Mavrogenis

If I run ESPlanner on my new Mac using Bootcamp, do I need a copy of Windows in addition to Acrobat PDF?
Can I use a different PDF program (e.g., PDFelement)?

You would need Windows to run the program. I don't believe PDFelement works.

I would highly recommend you just use MaxiFi Planner https://maxifi.com It's more robust in many ways and you don't run into these OS issues.

Dan