With its very on-the-nose name, Ad Blocker is a rather simple, but still functional, ad blocker for Google Chrome.
Since Ad Blocker has not been published to the Chrome Web Store, you need to download the ZIP file from the repo on GitHub or at https://ad-blocker.zacharyrude.repl.co/.
Once the ZIP archive has been downloaded, extract the adblocker-master folder. Since it is a Chrome extension, you need to have Google Chrome installed on your computer. If Chrome is not installed on your computer, download and install it from https://www.google.com/chrome/; otherwise, it will already be installed (e.g., if you're on a Chromebook or Android device), and you can simply launch it.
Assuming that Chrome is installed, go to chrome://extensions/, click on the "Load unpacked" button, select the extracted adblocker-master folder, and you're all set!