Clean the wall with liquid soap and water using a sponge to remove debris. Let dry. Sand it with 80-grit sandpaper. This allows the adhesive to grip the wall more firmly.
Apply adhesive or silicone caulk to the back of each stainless steel sheet. Place dots in the corners, then cover the rest of the sheet with a zigzag line.
Press the sheet firmly against the wall. Depending on the type of adhesive, you may need to pull it off and press it on the wall again, applying firm, even pressure. Follow the instructions on the package of adhesive to see how long you need to apply pressure until it sets. Some require that you tape the sheet's edges to the wall until it sets.
Let the sheets rest overnight. Wipe them down with a stainless steel cleaner and soft rag. This gets rid of fingerprints.