Adding an HTML Widget to Upfront

So, a friend is opening a hotel. He asked me awhile ago to do his website and I agreed... without really knowing what it would entail. I mostly do small business webpages or pretty simple stuff (using Upfront mostly). I found out he contracted a company that does online/cloud booking. The company sent him an HTML Widget to install on his website... but I can't figure out how to get it work at all.

The zip they sent comes with 3 folders (css, images, and js) and a TestWidget.html files. All the instructions say is to upload the three files to the same level as the webpage you want to add the widget to and then copy in the html to the page.

Problem is, I'm using upfront and Spirit theme to make the webpage. It's structure is much different than a standard html site (or so it appears).

My first thought would be to upload everything to the uf-spirit folder and then paste the html into a html code box (from draggable elements). The html won't even save and when I exit Upfront, it still just says "Enter your markup here..."

There is a note that says, "If you are using WordPress and adding the calendar widget to a PHP file then you will need to add <?php bloginfo(‘template_url');?>/ to the “href”"
I've tried this as well, but to no avail. It may be because I'm unsure about 'bloginfo' and 'template_url'. Should that be replaced with 'uf-spirit' and the site url? Or am I totally off with that?

So, does anyone have some advice on this? It'd be greatly appreciated. I can provide other info if anything I've written is unclear. Thanks!