Use your favorite web browser to find a video on YouTube. Then right-click it and copy the link to the clipboard. You can also drag and drop the video link onto the application window.
Open YouTube Downloader, or switch to it if it's already running, and click the Paste link button on the toolbar. The video will be added to the list and the app will automatically fetch its details.
To change the output format, click the middle button on the toolbar. In the new window you will see formats and settings for video and audio download modes. Saving in original quality (without conversion) is the fastest method.
Use the switch to choose between video and audio only download mode. In audio mode the app will extract and save just the soundtrack.
By default the app saves videos to the Movies folder and audio to the Music folder, in a subfolder called Downloaded by MediaHuman. To change this, open Preferences and switch to the Video output or Audio output tab.
Now everything is ready. To download a single video clip click the Start button next to it, or use Start all on the toolbar to download everything at once. You can continue adding more videos to the queue while downloading is in progress.
Once the download is complete, click the Locate button to open the file in Finder (or Explorer on Windows).