harunmushod
Explorer
Assume that the rules being used are OSE Advanced Fantasy, so AD&D1e or OSRIC scenarios might be ok too. But the important thing is that both players and DM are new.
This would be my suggestion.I'm a big fan of Tomb of the Serpent Kings. It's designed in an intentional way to teach players lessons about old-school dungeons. It's also free!
The one negative I'll mark for it is that early in the dungeon you are expected to "save to dodge", but a lot of old-school games don't have a singular concept of dodging. You'll have to choose between Wands & Breath Weapon depending on the circumstances in OSE.
It's also extremely deadly for new players and it doesn't offer support to DMs in places where they might expect it. (I hope you like coming up with names on the fly, because almost no one in the keep has them!)B2 Keep on the Borderlands. It’s the classic B/X module.
I always forget about that one. It really is a great intro adventure. I've even recommended it before. D'oh.In contrast, Tomb of the Serpent Kings is designed by Skerples, one of those designers who thinks deeply about RPG design and utility at the table. It's intentionally designed to teach players and DMs how to run an old school game.
The tree full of kobold archers, which is almost certainly the very first encounter at the caves, when the players are just looking around, is hilariously deadly.KotB is really good if you have around a dozen players. Less than that, they'll constantly get slaughtered by the always-hostile demihuman gank squads in every single cave.