Size: Prior to application, align nails with tab sides facing your cuticles and find correct size for each nail. When you are in between sizes go smaller, not larger. 
Prep: Wash hands with soap and water and dry thoroughly. Use included cuticle stick to push back any excess skin. Wipe nails with the enclosed prep pad (the most important step), to clean nails for better adhesion. (You can use rubbing alcohol in place of or in addition to prep pad.) 
Apply: Peel backing from nail then press it down on your natural nail, in the center and at both sides at the same time. Hold for 30 seconds. (Press on thumbnails last.)
If there is exposed adhesive, brush clear nail polish between your nail and the imPRESS and press down.
Wait at least an hour to wet hands or file nails if desired..