Correct exposure therefore stands for the right amount of light to be captured. From this one can deduct that exposure directly depends (or is defined) by two parameters: time and strength / intensity of the energy (= light). Time is defined by shutter speed, strength is defined by aperture. ISO speed here would be the sensitivity of the material to the energy which needs to be taken into consideration as well. Since we have 3 factors here the old rule pf structured experimentation applies: keep one or two factors constant, change the other one(s) and watch the outcome.to submit or make accessible to a particular action or influence <expose children to good books>; especially: to subject (a sensitive photographic film, plate, or paper) to radiant energy
Keeping constant here means: define one or two parameter according the situation, e.g. low ISO and f/11 for landscapes; high ISO and fast shutter for F1 race; low ISO and f/2.8 for portraits .. that's the part of the photographer's brain.
Enough theory, let's get out into the sun