Mark a plumb line on wall to be covered using a spirit level. Measure and cut wallpaper in lengths to suit, adding a few extra centimetres for variances.
Working 1 paper width at a time, use a paintbrush to apply a thin layer of wallpaper paste to wall at top and bottom. This is optional, but will help prevent top and bottom edges of wallpaper lifting.
Place paper face down on a large, clean workbench. Use a roller to lightly coat back of paper with wallpaper paste.
To carry each length of wallpaper to wall, fold pasted face over itself so it doesn’t flap around and get glue on things.
Standing on a stepladder, position top of your first length of paper in line with cornice. Release end of paper so it lies flat against wall and line up with plumb line you drew in Step 1.
Use a clean sponge to smooth out wallpaper, working from middle to edges.
Trim paper at cornice and skirting using a utility knife.
Trim paper at corners with a utility knife against a metal straightedge or wide scraper.
Allow 24 hours for paste to dry before painting, then cut in as usual with a brush and use a roller to coat the rest.