Simply pop it in your machine!
DETAILS?

Ideal to use on Cotton, Linen and Viscose Fabrics
Synthetics such as Polyester will not dye, though synthetic mixes such as Polyester/Cotton blends may dye to a lighter shade
Unsuitable for delicate fabrics such as Wool or Silk
It is important to consult the care instructions of your garment or fabric, to ensure suitability