You are not listening. It isn't a part of making tiles... You need to understand something. Paint allows you to recolour things too, changing their colour. here is a tool in there called Eyedropper (icon looks like a tube thing). Using this then clicking a colour makes your brush tool use that colour.
Your problem is 2 things - lack of understanding, but also lack of caring, as if you really did care to learn, you would question what I said more than once, without giving up.