Crop the decal into desired shape.

Place it on a cotton pad soaked in water.

Leave it for 10-15 seconds or until separates from the paper back.

Use a tweezer to detach the top part with the design.

Place it on the nail, on a sticky layer of base coat or color.

Fit it perfectly to the nail.

Do not leave excess on the sides, as that may get peeling or chipping of the stickers from the surface of the nail.

Apply top coat and cure.  

Optional: Apply a thin layer of bond or non acid primer before the top coat for a better adhesion.