Unfold a clean nappy and slide the back half, where the folded sticky tabs are, under your baby. Pull the front half of the nappy up to your baby's tummy. Make sure that the part of the nappy between your baby's legs is spread wide. If it’s bunched up, it may chafe your baby and make them uncomfortable. Fasten the nappy by unfolding one of the tabs, pulling it across your baby's tummy, and sticking it down. Repeat this with the other tab. The nappy should be snug, but not so tight that it pinches.