Our pocket nappy comes with 2 inserts. The inserts slot into the pocket at the back. Use one or two depending on required absorbency. All of our inserts are a mix of bamboo terry layers and microfibre layers.
3x4 snaps on the front. Take any of the three bottom rows of the snaps up to the top row of three to adjust sizing. Using the bottom row achieves the smallest fit. Using none of the snaps achieves the largest fit.
Put it on like you would a disposable nappy and fasten it with the snaps to get the right fit for your baby. It'll need to be snug but not tight and certainly not gaping away from the skin. Make sure the groin elastic fits into baby's underwear line.