Place the potty chair in the most comfortable room for the child. The family room, for example, is a place where a child tends to play and spend most of her time awake. Allow the child to examine the potty chair on her own. Explain how the potty works when the child shows interest. Keep the potty chair in the family room. These measures help a child adjust to the normality of the potty before using it.
Sit the child fully clothed on the potty once per day just to get used to what it feels like to sit there. Then sit the child on the chair with a diaper on before moving to undressing to use the potty. Explain that this is how everyone uses it.
Stay with the child when he uses the potty. Children often squirm because using the potty -- at first -- is still unfamiliar and can be scary. Kneel beside the child and place your hand on his hand or knee. A parent's physical presence and/or a minor touch can disarm a child and help him relax.
Read to the child while she uses the potty. Reading a child's favorite story, for example, redirects her mind to a calm and imaginative place. This effect relaxes the muscles of the body and helps a child remain still until her time on the potty is over.