To prevent any damage or deformation, you should remove the wallpaper from its original packaging as soon as you receive it and gently loosen the roll so that it is not tightly wound. This process allows the wallpaper to relax and helps avoid creases or bends. Leave the wallpaper in this loosened state for at least 24 hours before you begin installation. 

When preparing the wall for wallpaper application, ensure the surface is smooth, clean, and completely dry. Start by filling any holes or cracks with an appropriate filler, then sand down any bumps or uneven areas to create a flat surface. After sanding, wipe the wall with a damp cloth to remove any dust or debris, then allow it to dry thoroughly for at least 24 hours before proceeding with wallpaper installation. If the wall has been recently painted, you should wait between two and seven days for the paint to fully cure, depending on the type of paint used, to ensure the wallpaper adheres properly and lasts longer.