You just need to copy page URL, or right click on the video to select "Copy video address", then paste the URL into the search box of Distill Video (http://distillvideo.com) and press “Start” button. After waiting 2-3 seconds, the video section showed, choose your preferred format and right click the "Download" button, then click "Save link as..." to download the video or audio into your computer or phone.
That said, with Android it is possible to install apps without going through Google. The latest is InsTube – Free Video and Music Downloader just for Android—you can only get it at InsTube's site. You download the APK (Android application package) file to sideload on an Android device. Find it in your device's downloads and click it to install. (You may have to go into your security settings and enable "Unknown sources.") There is a similar side-load app from YTD.
The same as you do to download any other videos. You just need to choose the 1080p or 4k format in the video result section, sometimes it is in the "video only" section that without sound, then you have to download the audio file (M4A) in the same result section, then you can load the video file and audio files together on your computer using the video playing software, such as VLC. You also can combine the video and audio files by using ffmpeg. Some youtube video does not have HD format originally, in such case, you definitely can not download any HD format video.
DistillVideo supports to run in any browser accross any platform, regardless of whether you are using Windows, Mac or Linux, Android, iPhone. Provide audios/videos in full file formats including MP4, AVI, MP3, WEBM, FLV, 3GP, M4A, etc. It also supports HD videos of 1080P, 2K, 4K and 8K. It can convert any online video to MP3 for free (free MP3 converter). Subtitles can be extracted and downloaded as well. No need to install any annoying softwares or apps that may infect your computer or android phone. It is the best and free downlowder to download any video from any site using url online.