More biscuits...shortbread.

The best, and worst, of home-made biscuits, and an excellent one for the beginner to train on.

The word "short" refers to the fat content, (high)

First find your recipe: and I can tell you right now that most of the common shortbread recipes are much the same; they usually recommend a 3, 2, 1 ratio of flour, butter, sugar, in that order. Typically, let's say, 9 oz of flour, 6 of butter and 3 of sugar.
The butter is rubbed into the flour with your hands until amalgamated into a rich sandy mixure: the sugar is added, and the whole mass squeezed together until it forms a dough.
You may find this process frustratingly dry but DO NOT ADD LIQUID! Keep kneading, and your warm hands will bring it together into a smooth ball of dough eventually.
(If your dough has got too sticky/greasy in the kneading, you can lay it aside, or chill it, for a while, and the dough will firm up.

Usually this will be pressed out into a tin, or rolled and cut. Don't make it too thin or it will burn. And don't make it too thick or it will be dreary chewing. (Not thinner than a 2 euro coin, probably not thicker than about 7 mm, is the best I can suggest.)

Check the temperature of the oven: most recipes say something like "a moderate oven, about 350 F or 180C"- this is too high!

Bake slowly at about 325F or 160C and start checking at 9 minutes, then 11 minutes, then 13 etc.
Don't let them brown, a light suntan towards the edges is enough.
How much heat could it take to cook a bit of flour that thin? how long for a pancake on a pan, by way of comparison?
The sugar and butter are edible raw anyway, you're only cooking the flour - don't overdo it!

Remove and cool promptly - sprinkle with caster sugar. Done!
Very, very plain biscuits - there are many improvements possible, you bet. But more of that anon.