>>87410778It's easy!!!
4chan sounds has a small tutorial but you basically have your file, your sound and you put the sound up in catbox and write it on the filename of the picture or video you're going to upload (make sure the video doesn't have audio channel) making sure you write any '/'s as '%2F' like this
[sound=files.catbox.moe%2Fswdbf2.ogg]
4chan sounds can do it for you, too
If you're wondering about clipping things I personally use mpv with the webm add-on but I do know people also use yt-dlp but I'm too dumb for that!