With Francis Bacon essays, the first barrier is the age and antiquity of the language. It is often difficult to make out the sense of even one sentence easily. The whole essay can often seem to be just some kind of alien way of speaking.
However, when you crack through the language barrier, you see that what he is saying actually makes a lot of sense. There are even some really good insights to ponder. So therefore, I urge you not to despair in your study of Francis Bacon essays: they are difficult to crack but there is good stuff in there if you can get to it.
"Simulation and Dissimulation" is an essay about whether you deal honestly with the world or whether you put out a false front. "Simulation" is a false front, because you are "simulating" to be something you are not. "Dissimulation" is even worse, because then you are actually pretending to be something you are not.
So when would you use simulation and dissimulation?
In the military, in politics, in big business.... Lots of places in the world and society.
Now the really tough question: do you personally use simulation and/or dissimulation for any purpose?