This one isn't a quick result but hear me out. It's maybe even relevant to a lot of adults too.
Maps and navigation aren't cool. It makes you think of geography at school and it's something that can be hard to get engagement with. I've no shame in saying I absolutely love maps and will always use a paper map and my skills and experience over a GPS. I learned to navigate with maps as a kid in Scouts and I've continued to use those skills ever since. Being able to navigate (and prove competence to adults) opened up loads of adult-free adventures which were, of course, amazing. Navigation is something that slowly becomes built-in and natural which will remain as long as you use it.
Most teenagers will be riding trail centres or woodlands that they know pretty well, so what's the relevance here? Well, they'll get older and want to start riding trails they don't know. Those trails might be on an app such as Trailforks but if there's one way to kill a ride's flow, it's to be constantly checking your phone for it to tell you where to go. This is where your navigational instincts and experience comes in! And, of course, the fact that being lost can put you in serious danger of having to spend the night outside when you hadn't planned on. Further, the best riding isn't on any trail app
You will only learn how to use a map if you actually use one regularly and you want to learn. It's not rocket surgery or some black magic and once you get the basics, it all comes together pretty easily.
It is something you can teach yourself with some online guides and books. There are companies out there running navigation courses for adults but I haven't seen any specifically for under 18s.
Ordnance Survey are the go-to for maps and they have two decent resources you should check out.
The first, Mapzone, is a bit childish and cartoony for older kids, but it's a great starting point as it's very basic. It covers scale, contours, grid references and bearings.
Then move on to their Beginner's Guide, created for adults but will be easy enough to follow for most teenagers. They may have even covered some of this in school.
Next, buy a paper map of where you live/ride or, even better, an OS Subscription. £24 a year gets you the entire Explorer and Landranger mapping which covers the whole of GB online. You can plan routes online, then download them to the app on your phone, but the real deal is being able to print sections of map to take with you!
Go through the resources above and use a map of your area to see how it works in practice. It's a lot easier to understand contours, for example, if you have the real thing in front of you, rather than a photo.
Then create a route on OS Maps that you're very familiar with. Natural singletrack trails may not be printed on the map so best stick to bigger tracks and trails for now. Print the map without the route marked on it (the route can hide useful map details, draw it in with a highlighter pen if you need to) and download the route to your phone. Go for the ride and stop every now and again to use the paper map to check you're on the right course and match up what's on the map with what's around you. There's no pressure as you know where you are in the 3D world and that you've got the app to give you a reasonably reliable confirmation that you're right. This will build up your confidence that you can relate the real world to a printed map. It's with this increasing confidence that you can test yourself more and more until you're perfectly happy setting out on a totally new route without using electronic navigational kit.
For advanced reading, and to bring out your inner map geek, I'd recommend Navigation in the Mountains, published by Mountain Training.