Place a scrap of corrugated cardboard larger than the chair on the ground to create a protective work surface. If carpeting, a lawn or other soft surface are available for the chair, the cardboard is not needed. Set the chair on its side atop the cardboard or soft surface.
Inspect the bottoms of the chair legs to determine if any have damaged caps that need to be replaced. If so, pry the old caps out by sliding a putty knife or flat-head screwdriver between the end of each cap and the bottom of its respective chair leg.
Press the new cap into the opening on the bottom of the chair leg with your fingers. Tap the cap gently with a rubber mallet while holding the chair leg steady with your other hand. Keep the cap end perpendicular to the chair leg so it sits flush with the bottom of the leg once set completely in place.
Repeat Step 3 for the remaining chair legs, ensuring that each cap is pressed fully in place. Set the chair back upright.