What makes a scenario playable
A setting is not a scenario. "A tavern" gives a roleplay nowhere to go, while "a tavern where the person who betrayed you just walked in" gives it a whole evening. A playable scenario has three parts: who you are, who is on the other side, and what stands between you. A lighthouse keeper and a stranger who will not give a name is already enough. Type as much of that as you have, even if it is only half a line.
How the generator fills the gaps
The AI reads your line and asks up to three questions about the parts it leaves open, such as how the other character feels about yours, what your character wants tonight, or where the first scene opens. Each question comes with options, or you can type your own answer or skip it. If you have nothing at all, press Surprise me for a fresh idea. Then set the heat and the chapter length, and the scene opens in the full app on a free account.