Hoe download ik een video van YouTube of een andere site?

Point at the video in your browser and click the Download video button that appears over it, or paste the page's address into Tasks → Download video from a page. GDM lists every quality the site offers, with sizes; pick one and it downloads like any file. It uses yt-dlp, which supports thousands of sites. Download only videos you have the right to. See Download a video from a page.