I ran an introduction to D&D program for teens ages 12 and up at the local library for five years. I have an introductory adventure you're welcome to use. Shoot me an e-mail. Use my TMP member name, the ubiquitous "at" symbol, and the domain aol.com. (That should confuse the bots.) The adventure is designed to be played in no more than 2 three-four hour sessions, and introduces everything from the importance of searching for traps and secret doors to turning undead. And with only 9 rooms, it's an easy dungeon to explore.
I'm more of an old school gamer, so I'm more adventure oriented than character oriented, but the old ways work fine with the new system, too.
Be aware if you're an old school DM that 5e is not really amenable to house ruling. It's a very tightly designed system; you're better off sticking as close to the book as you can, especially with how magic items function. It's too easy to overpower home brewed stuff.
Also, you'll need to stay on top of what special abilities the player's characters have as they level up. 5e is a higher power game than the older stuff. The various classes and subclasses can wind up being able to do things you may not expect, which can mess up adventure planning if you're not careful.
Finally, magic doesn't work the way classic D&D used to do it, and the spells are often different in capabilities than you may remember— some are nerfed, some are actually more powerful, and some are highly restricted in their utility.
I haven't had a chance to really read through them, but there's a series of more or less thematic "how to" books for kids called The Young Adventurer's Guides published by 10 Speed Press and licensed from WotC. They don't deal with the game rules, but instead with the various concepts such as fantasy races, types of armor, types of spells, monsters, etc.. They offer strategies and advice for handling the various things which come up in the game, and might at least be helpful for your players to peruse.
Also, the Starter Set and Essential Set have complete campaigns designed to take beginning players and their characters through several levels. (Leveling up is considerably more frequent in 5e). They're a good place to start.