Place a pair of safety gloves on your hands.
Insert the putty knife underneath the stop pieces. Gently pry up the stop so you don't damage it. When you are removing the last stop, place your hand across the glass to prevent it from falling toward you.
Grip the edge of the largest section of glass. Lift out all glass pieces.
Run the edge of the putty knife along the frame to remove any old glazing compound.
Insert a tube of glazing compound into a caulking gun.
Squeeze out the compound evenly all along the frame where the edges of the glass sit.
Set the new piece of glass into the frame. Hold the glass into position.
Push a few glazing points into the frame wood. One end of the glazing point sticks into the wood between the frame on top of the glass. The other end sits on the outside of the frame on top of the glass. They help hold the glass in. Insert at least two glazing points on each side of a small rectangular piece of glass.
Place the stops in the exact position where they sat previously. Tap in small wire brads with a hammer close to the original hole locations. You may use the original holes, but making new holes may help secure the wood if the original holes have widened since the install.