Two ways. One you could look through the viewfinder and see the effect of the simulation, press a button to set the simulation for the jpeg and then go back to Provia to see the real scene. Or if you have a simulation you like, then select it for the jpeg and then shot with Provia with the jpeg having the simulation.
Should be able to do a custom setting with the simulations you like and then be able to shoot looking at the "real scene".
Looking at the real scene is important to see the various colors in the scene so you know what you are getting rather than having to see a simulation.