I downloaded the windows version and it only came as a file how can I access the simulation. Please can someone tell me?

You need to extract the zip file somewhere, your desktop would be easiest, and then look for the .exe file inside. That is the simulator.

remember if when you click on the .exe and it doesnt work still you may need to right click on it, go to properties and click the little checkbox that says something about unblocking the application. it was extremely annoying figuring that one out for me