Tools: office knife
The first strip is usually glued from the window side. In addition, leave the wallpaper protrusion large enough to cover the tilt of the window.
With a utility knife, carefully trim the protrusion along the upper slope of the window and along the sill line. The protruding part is used to cover the window tilt.
Tools: edge trimming ruler, utility knife
The protruding joint between the wall/ceiling and the window tilt must be cut neatly.
Tools: plastic trowel, utility knife
All protruding parts in the window bevel area must be carefully trimmed!