Any scenario not marked "Locked" can be played by clicking on it.
"Locked" scenarios are unlocked by completing others. Currently the only way to see which
scenarios are required is to cheat and look inside the module's data. This may change in the future, though.
Also, all scenarios currently only have a finished/not finished state. In the future, multiple completion codes
will be added so that instead of completing a scenario, you will need to get the right ending.