Select a clean ice tray that is large enough to make the amount of ice that you want. They come in a variety of shapes, sizes and textures.
Fill each receptacle of the ice tray with the liquid you have chosen, whether it be bottled water, tap water or a fruit juice of some kind. Fill each one all the way full. Standard ice tray receptacles are between 1 and 2 oz. each in volume. If there are ridges or indentations in the ice tray receptacles use them as guides on how full to fill each one. This keeps the water from overflowing in the tray.
Place the filled ice tray carefully into your freezer.