The seat should raise and lower by lifting the lever on the side. It worked for a few minutes, then while sitting on the seat, it suddenly dropped to the lowest position unexpectedly (throwing out my back)! Now the seat height cannot be controlled. Wayfair was great with the refund process. 
Other notes: the back of the chair is for looks only. As you can imagine, it's hard wood that digs into your lower back. The seat cushion is decent, not too hard but not particularly comfortable. It is rather wide. The style is nice and would have looked great in our kitchen.