Make sure the centerlines are in exact alignment, and pull the top down tautly to the roof. The material will bond immediately, so positioning is critical before bringing the material in contact. Start at the center, working outwards to the corners of the roof. Two or more helpers make the job easier, but it was done solo here. Avoid pulling the material up and adjusting the position more than absolutely necessary, since lifting usually causes the glue to lift from the roof, compromising the bond. Another pitfall of repositioning is the adhesive will bead up, with the wads of glue creating lumps that will show through the material. Position it exactly in the right place the first time it makes contact.