Solo engines are frequently designed to work with scenes and threads. Scenes are like the scenes of a film. If your characters are in the tavern and then decide to go and seek an audience with the local priest then typically that would be two scenes and you could skip the travel in between. I say typically as you will see later things can happen.
Threads are individual story arcs or plot hooks that can could take the story in a different direction or change the way the character sees things. Typically in a solo game there will be several open threads. You can include the main plot you are on but also any unfinished business in your characters backstory and those from your NPCs backstories just to get you started.