How do I call a function using DAT.Gui like a button?

I barely know JavaScript, but I know enough to know how to make function connections, timers, CSS editing/HTML editing, and more, but I don't understand how to use this "dat.GUI", as my current project design... well.. It sucks.

All my buttons are just <a> links I used to make a minimalist design. Just look at it: codepen.io.. So I wanted to move into Dat.GUI, but I don't know how to make a GUI, as all the tutorials I have attempted usually wound up resulting in an invisible GUI (it doesn't even show up) and nothing works.

So I come here to ask if anyone has some information and possibly some examples I can work off of? In my project that I posted above, I have included the code I made so far for the dat.gui portion in the very bottom of the JavaScript.

For those who are going to post an answer with this example included: chromeexpirements DON'T. I'm not looking for this again and again, I can't figure out how to use it from that, and it doesn't really explain it in a level of detail I can understand (I'm not an inept javascripter). I also started using this example on codepen for learning: codepen.io

The amount of code I have in my project is a bit... Unsizeable to use/paste here. Here is my current code to run off of. Say I have function raintest() { intervalID = window.setInterval(myCallback, 100); } that runs a interval that runs myCallback every 100 miliseconds, which clicks a button in my screen that does something, that's not that important, but how would I run function raintest() with dat.gui and other functions?

Here's the dat.gui code I have so far and am trying to work from. So far all it does is show the close/open tab, and I don't know how to add buttons to the list:

window.onload = function() {
  var gui = new dat.GUI();
  gui.add(text, 'message').onChange(setValue);
};

Current results are empty, I don't know how to connect the JavaScript code to the dat.gui correctly. It just loads a tab for the base GUI at the moment. I actually want it to be able to open, and have all my buttons in it with all my functions, so I have my cloth customization options readily available without filling up the top of the screen 24/7.

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