To use a window repair kit, place your car in a cool, dry place, such as a garage or shaded area; clean and pat dry your windshield so the kit adheres properly; take an adhesive strip from the kit; and remove the backing film before adhering the strip over the center of the chip. Take a blunt instrument, and rub the film to press it into the chip while scraping off the excess.
Use the adapter tool from the kit, and attach it vertically to the film. Take the adhesive syringe from the kit, remove the cap, and secure it to the adapter while ensuring the adhesive doesn't fall onto the car's paint. Steady the syringe in one hand while pulling the stopper back with the other for one minute to remove air from the area. This allows the adhesive to fill in the crack without bubbles or other anomalies. Release the handle, and push the adhesive into the chipped area.
Repeat these steps as needed until the chip is filled. Take the syringe and adapter off the glass, and clean any spilled glue with a towel soaked in alcohol. After a few hours, the adhesive hardens, allowing you to remove excess material with a sharp razor blade. Even out the area so it's flush with the rest of the glass.