@RithyI have a starting point planned, and I also have a general idea about where the story can go. I'm borrowing from tabletop games or video games like Skyrim in that the journey to your end goal doesn't have to be linear. Ideally, the "party" will use the OOC to discuss strategy.
For example if the party is dealing with a particularly difficult noble someone might post in the OOC: "Okay guys, how should we deal with "insert noble here"? Do we think they're lying? Etc." Sometimes your fellow players will have more insight because I've privately messaged them about something only their character picked up on (based on their backstory, race, traits, etc.)
The RP will have a quest log, and I'll update it to let you know where to start or when you've accomplished something as a part of the quest. I don't want to railroad (though there may be some small bits of it if necessary), but I will do everything I can to guide everyone through so that the experience can be enjoyable whilst still having an element of adventure. It is entirely up to the players how they interact with the world, and in turn how the world interacts with them.