1. From inside, use a utility knife to slice through the old paint along the outer edge of the stop beads, and in between the stop beads and sidelight sash.
2. Then, use a stiff-blade putty knife and flat bar to carefully pry the stop beads from around the sidelight sash.
3. Move outside and use the utility knife to cut through the paint bead around the exterior of the sidelight.
4. Use your fist to gently tap the wood frame of the sidelight to free it from the opening.
5. If your front door has two sidelights, repeat Steps 1 through 4 to remove the second sidelight.
6. Trim the new sidelights to fit the existing openings. Cut them to length with a circular saw, and trim them to width with a hand plane.
7. Brush a coat of exterior-grade primer onto all four edges of the sidelights.
8. Apply a continuous bead of acrylic-latex caulk around all four sides of one opening and press the sidelight into place.
9. Reinstall the original stop beads around the inside of the sidelight. Secure the stops with a pin nailer and 1-inch pins.
10. Repeat the previous two steps to install the second sidelight.
11. Prime and paint the inside and outside surfaces of both sidelights.