If you're just looking for a basic guide, do the following:
Upload that dist.zip file on the LibGDX Html section of the game uploader, and let Static Void Games handle the rest!
Those are the basics, but if you want more information, keep reading:
This guide goes through the process of creating a libGDX game, exporting it as an HTML project, and uploading it on Static Void Games so other people can play it. This guide assumes that you already have an IDE and a project setup. If you need help with that, follow the instructions here first!
Some guides might have you do a "GWT Compile" from your IDE. This allows you to debug your project from your IDE, but it also creates a ton of extra files. That's not a big deal if you're running your own server, but since you'll be uploading your game, these extra files will just waste your time (and might even cause the upload to fail). So let's get rid of them!
If you did do a "GWT Compile" from eclipse, all you need to do is delete the html/war/html directory!
Open a command prompt to your top-level project directory. Then type:
...and hit enter. That will package your game as an html project.
The above process creates a folder that you only need if you're serving your own files. These files can get pretty huge, so let's delete them.
After deleting the dist/WEB-INF directory, zip up your html/build/dist directory. Do this using whatever file archiver you want. I use 7zip, but your default zip program should work fine.
This should create a dist.zip file. This is what we care about!
From the game editing page, go to the "libGDX HTML" section. From that section, upload the dist.zip file you just created. Choose what kind of page you want to display, add some text for the controls, and let StaticVoidGames handle the rest!