Before sticking a product, wipe your surface to make sure it's is smooth, clean and dry.
Remove paper substrate from your sticker (grid paper on a back).
Place sticker on a wall, use a scraper or any plastic card to flatter vinyl from center to bottoms along the illustration.
Carefully remove transparent film.
Recomendation: Try to apply on a wall a small sample "star" before sticking the main product.