You will need a juicer/blender.
In a blender/juicer, add the carrot, pineapple and ginger (you may have to do this in batches). Pour enough water to cover the ingredients.
Blend until smooth.
The juice will keep nicely in an airtight container for up to 48 hours in the fridge but is best fresh within a few hours. Give a good stir before drinking.