Stand back from the corrugated siding and decide where the signage should go, considering factors such as lettering being blocked by parked cars or obstructed by landscaping features.
True up the bottom of the sign or letters with the space it will occupy. Use a carpenter's square to line up the side and bottom of the signage with the side and bottom of the building. Mark the alignment with a fine-line marker, using the yardstick to extend the baselines.
Step back and make sure the signage reads as being straight.
Use painter's tape to temporarily fix the sign or individual letters along the guidelines.
Space individual letters a uniform distance apart, separating words by a larger space.
Step back and look at the signage. Adjust it as necessary for best effect. Mark the position of flat signs and/or individual letters.
Mark the location of the highest ridge points on the top and bottom edges of flat signs all along the length of the sign. Place temporary small post-it tabs over ridge high points, if using individual letters rather than flat signs.
Remove signs or letters without disturbing the temporary post-it tabs. Place them face down on a clean padded surface such as a blanket.
Clean the corrugated siding where the sign will go with a clean cloth. Don't remove placement markings.
Put strips of double-sided adhesive suitable for outdoor use on the reverse of the flat sign where the markings on the top and bottom edges indicate the ridge high points will be. Use either double-sided tape cut to appropriate sizes or silicone to apply to the reverse of the letters. Put tape or silicone in the areas indicated by the temporary tabs on the fronts of the letters.
Apply the signs or letters to the corrugated siding, as indicated by the baselines, and press in place. Use painter's tape to fix letters with silicone on the reverse of the siding until the silicone hardens.