There are tons of videos on YouTube for Maglites. It's also one of the things that are looked at as a waste of time to many, because there are so many different lights in the world, all needing different tear down methods.
See, it's kind of like this, if you have a good amount of common sense about tools and taking things in general apart, then you don't really need the information, since just looking it over allows you to figure it out yourself easily, but if you struggle with simple tear down ability, like taking a flashlight, or headlight, or some other object apart, then people don't waste a lot of time on making videos on things like that. I am not saying that is right, but it about how it is on a lot of simple stuff.