How much force you need to apply has VERY little (not to say NOTHING) to do with SolidWorks Simulation, as it would be pretty much the same force you are gonna use in every design validation process either by hand, FEA or whichever kind of analysis you decide to go for.
What are you designing? What are the operating conditions? Whats the operational inputs/outputs? Those are the kind of question you need to ask yourself when trying to calculate the loads your design is subjected to. Those are you SW-Sim INPUTS, which means you estimate them WAY BEFORE even opening SolidWorks Simulation.
Having an accurate estimation or actual calculation of input forces for Simulation is critical to the accuracy of your results.
The best you can do without having accurate forces to run is to point you in an direction as to where the weak points of the design are. But you won't know if you've reached the limit of the materials due to unknown forces.
Also critical is to know how to apply your restraints, but that's a whole other conversation.
How much is 10N? It is 'about' 10 average-sized apples.
ALWAYS do a FBD before setting up an FEA.