Having trouble understanding how to customize this mindmap library I found

I wanted to have a mindmap application I could customize and tweak to my own personal style, and found a library after doing a search called jsmind Link: https://github.com/hizzgdev/jsmind Currently: the way it is setup is that it has a "title" field, and when you click on a node and edit its input box, the text you typed in gets shown. What I want: To be able to add an additional field to each node where I can add a URL, and ultimately make it so that clicking on a node will open that URL and send me to that page. So even though the title I type in will show up on the node, the node itself has a URL field that can send me to the site. I tried to play around with this but got lost as i've never worked extensively with javascript before, other than some small scripting tasks. Here's what I tried to do: https://github.com/ad1994/mindmaptest/blob/master/js/jsmind.js I tried to mirror what the "Title" setup was like (for adding the title)...but got lost in the process. I tried to create a second input box for the URL input, as well as try and make a node consist of a new field I made called lnk (Link) for the url. Just getting "undefined" and not being able to get a second input box working with the "lnk" field. Any guidance would be appreciated.