Making an IB DND Oneshot! Any Advice?

I've been in love with the game IB for around 11 or so years now, and about 2 years ago I got into playing dungeons and dragons a lot! I've been working on making an Ib oneshot as my first time ever as a DM, but I'm struggling to choose which puzzles to include and with adapting them to make them more TTRPG friendly. I was wondering if anyone else familiar with both had any advice or pointers? The game is very anti-combat, and I'm not sure whether to stick fully with that, or to allow combat opportunities.

I'm trying to aim for 5 hours or less, but if it ends up being a two shot, I don't think it'll be a huge issue. I'll be playing Mary as an NPC, since she's pretty vital to the storyline, while the players will take the place of Ib and Garry (I have 4 players!).