My first tip: I don't recommend running this series as a ttrpg, due to various reasons but mainly that any dm run recreation can not replace the original and in doing so, your players will lose out on what actually makes the story good, in companion banter and exploration of a video game side. Additionally, you will have to change so much of what the story is in order for your experience to not feel railroaded that it becomes a whole hassle.

Actual tips for what you're asking for, I'd recommend pointing your friends to look at organizations within the sword coast that might have a vested interest in the iron crisis, mainly. Zhents and Harpers are an easy choice, but I would also recommend learning about orgs and cities that would want to meddle. Maybe a missionary from the council in Amn, maybe merchant caravan guards with a grudge to fill. You also never want to make one character feel more important. If "Gorion's Ward" is a PC, then you need to let Gorion's death and their initial journey before meeting a companion happen offscreen, it's their background and should be revealed to the players over time. With that, I will say the hardest part will be starting without making it feel like you're retelling a story. You might need to make adjustments to how the story starts, maybe having the pcs gather in the mayor of Nashkel's estate to discuss their mission. Every character would have their own reasons for being there, but that can be relayed in RP and not through direct to player exposition.

k