Browser Sync set up gone wrong

I followed all the steps from https://browsersync.io/#install, up until the last one (start BrowserSync). I have a folder, called MyWebPage1, that has 3 sub-folders : HTML, CSS, JS. Now each of these sub-folders contains a file, called either index, either main, with the apropriate extension. What do I need to do in order to have my index.html page refreshed everytime I apply a change to the file itself, or to the css file, or to the js file (being given how I organized the files)? I spent almost 2 hours trying everything : entering all kinds of paths, reinstalling BrowserSync multiple times and typing all kinds of commands into the command prompt (now I know the description of what I've been through sounds a little bit unprofessional, but after all, I'm new to web developement, just a newbie learning in order to earn a job). I'd say I could use some help :D!