Slide the seat of the chair into the grooves on the sides of the Tripp Trapp chair, positioning the seat so the child's thighs fit comfortably underneath the table and, in the case of an infant, the security strap fits around her waist. For older children and teens, use the footrest as the seat bottom.
Put the child in the chair and make sure she fits comfortably. Remove the child from the chair and make any necessary adjustments, then return her to the chair to retry the fit.
Slide the footrest of the chair under the child's feet and into the grooves on the sides of the Tripp Trapp. Make sure her feet reach the footrest and that the front of the footrest doesn't extend past the front of the chair legs.
Install the screws with a hex-head key into either the sides of the footrest or the seat, depending on their position in the sides of the Tripp Trapp.