Here’s a guide for how to include JavaScript:
https://developer.wordpress.org/themes/basics/including-css-javascript/
That script won’t work as-is, it’s an example for jQuery tabs and other controls usually have different event names for when they open. I checked the accordion documentation, but I didn’t see any events listed. If you’d like to send a URL with a map & accordion on it I’ll have a quick look and see if I can guess.