We’ve seen it a million times, but one more “how to make a real lightsaber” video isn’t gonna hurt. This one comes from HeroTech who built an extendable and retractable lightsaber and put together a tutorial on their website (for paid members only).
All jokes and mild snark aside, you should definitely watch the video as they’ve done a cool job of putting this all together and it’s a lot safer than some of the lightsaber prototypes I’ve seen that could burn you if you got too close to the blade (although they did point out that this was “potentially dangerous to DIY” so bear that in mind).