As you add information into each scenario column, you will see the four scenarios starting to take shape, but it is important that you remember that the worksheet is only a collection of information, the skeleton of your scenario.
The main differences between scenarios should be in the driving forces. Decide which domains or forces will be dominant during your next life stage, then vary those forces to change the scenarios. For example, if you expect your career to dominate this stage, use the upper line you drew when you extrapolated into your future on the Personal Domains page.. The one where everything goes right. That gives you the logics for your "Best Plausible" scenario. Use the lower line for your "Worst Plausible" scenario.
Once you have filled in the data for each scenario, it is very important to see how that information fits together. To get a better picture of the future, you will need to view each scenario as a whole, as a story.