Old-school riffery from Richie Valens. But the song is probably best known for Los Lobos’s cover version. The highlight of that version being the outro. Here’s the start of it in the same, uke-friendly, key as I used for the riff.
If you want to play it in the original key, move everything up 7 frets – something like this. It’s much more difficult but still playable.
Part of the Guitar Riffs for Ukulele series.