Show category in PHP page in another directory

Here’s my situation: I’ve got a site I’ve created that’s all static HTML. One of the pages is a calendar/events page (https://www.fpcanderson.com/calendar.htm). I’ve also set up a blog for the site (https://www.fpcanderson.com/building).

I’m wondering if there’s a way for me to make a category or page that they can update with their news and events that I can have show up in the HTML calendar page. I’m sure I’d have to convert it to PHP, but is there a way to include that category in an iFrame or as a PHP include? I’m a newb to this stuff, so I may be asking for too much here…I don’t know. Any help is greatly appreciated…