I know this probably sounds abit silly but how to I know when I should be using my scales to 'weigh' out the measurements and when I should use my measuring cup? I just came across this statement
Think of a 1 cup pyrex measuring cup which is marked 8 ounces (volume). One cup/8oz of feathers would not weigh the same as 1 cup/8oz of rocks!
So how will I know when to weigh and when to measure? I mayb just be having a blonde moments atm but its really bothering me lol. PLZ help

It does make a difference for sure and generally it is more accurate to weigh. But a lot of recipes are written using volumetric measures so unless it is something I use all the time I can't be bothered to convert the recipe, but just stick to the recipe as written. There are some rules of thumb to follow. Make sure all dry spoon and cup measures are level. When measuring flour, spoon the flour into the cup instead of scooping to avoid packing the flour in the cup. Read the recipe carefully, there is a difference between 1 cup sifted flour and 1 cup flour, sifted. When you sift the flour before measuring it will be more aerated so there will be less flour by weight to a cup, than if you measure a cup of flour, then sift it.