The top is separate from the bottom and connected by snap tap you sew to the pajamas.
The top opens at the neck for easy one and off for the head. It also has snap tab applied.
The pajamas are designed with feet attached .
This is what snap tape looks like. It is a webbed tape with snaps applied. It can be found in most fabric stores at the notion wall. It is by the yard so you can get as little or much as you want. The tape is designed to be sewn to garments.