Begin by clearing all items from underneath the sink to ensure you have an unobstructed and safe workspace. If the hot water has been used recently, wait for the hot water supply line and P-trap to cool to room temperature to prevent burns. Using a cleaning cloth and a mild degreaser or all-purpose cleaner, thoroughly wipe down the P-trap, both hot and cold angle stops (shut-off valves), and the water supply lines. A clean, dry surface is essential for a secure fit of the shield components.

Using a flexible tape measure, take precise measurements of all plumbing components that will be covered. Measure the length of the P-trap U-bend. Measure the vertical sink tailpiece from the sink drain down to the P-trap inlet. Measure the horizontal trap arm from the P-trap outlet to the sanitary tee connection in the wall. Finally, measure the hot and cold water supply lines, from the top of the angle stop valve body up to the faucet connection nut. Write down all measurements on a notepad to reference when cutting.

Lay out the shield components on a flat, stable work surface, preferably a cutting mat to protect the underlying surface. Transfer the measurements from your notepad to the corresponding shield pieces. Most pre-molded kits are made of a semi-rigid vinyl or PVC that can be cut easily. Use a sharp utility knife with a new blade or a pair of heavy-duty scissors/shears to make clean, straight cuts. Follow any score lines provided on the pieces. For your safety, always cut away from your body. Re-measure the cut pieces to confirm they match your required dimensions.

Start with the main P-trap cover. These are often hinged or two-piece designs. Open the cover and carefully position it around the entire P-trap assembly, ensuring it covers the U-bend, tailpiece connection, and trap arm connection. Align the seams and close the cover. Secure it using the fastening mechanism provided with the kit. This could be interlocking tabs that snap together, hook-and-loop (Velcro) straps that wrap around the cover, or plastic snap rivets that push through corresponding holes. Ensure the fit is snug and the cover does not slide.

Next, install the covers for the hot and cold water angle stops. These covers are typically molded into a bulbous or box-like shape to fit over the valve body and handle. Like the P-trap cover, they are usually hinged or two-piece. Snap one cover over the hot water valve (left side) and the other over the cold water valve (right side). Ensure they close completely and are securely fastened. The design should fully encapsulate the valve to prevent any accidental contact.

Take the trimmed tubular covers for the water supply lines. These covers are slit along their length, allowing them to be opened and fitted over the pipe. Start with the hot water line. Pry open the slit and press the cover onto the supply line, working your way from the top of the angle stop cover up to the faucet connection at the base of the sink. Ensure the seam closes fully. Repeat the exact same process for the cold water supply line. The covers should fit snugly and conceal the entire length of the lines.

Perform a final, thorough inspection of the complete installation. Visually check from multiple angles, including from below, to ensure no sections of pipe are exposed. Pay special attention to the hot water components. Physically test each shield piece by gently pulling and wiggling it to confirm it is securely fastened and will not come loose with incidental contact. Verify that the shield does not obstruct the sink drain, faucet operation, or access to valve handles if required by the design. The final result should be a safe, clean, and professional-looking installation that meets ADA requirements.