Anyway, when talking about the exposure triangle as our SRC photography lecturer has said, I think it would be prudent to consider what type of photos you are taking first and what type of effects you are striving to achieve before deciding how to set the parameters of the camera.
Also, one needs to take into consideration the amount of sunlight and where the sunlight is coming from before deciding the ISO, aperture and shutter speed to use.
Typically speaking, if you are taking photos of the F1 race, you will need to preset your shutter speed first and then the ISO. In this case, most people would be using Shutter priority where the camera will decide on the aperture to use after you have preset the ISO and shutter speeds.
For portraits and landscapes, you would probably be adjusting the ISO and Aperture only and would likely be using Aperture Priority on your camera.