A lining paper can be hung vertically since the width is almost certain to be slightly different from your wallcoverings and it is unlikely that the joints of the two would coincide.
However, to be absolutely sure – or if you prefer – you can always hang the lining horizontally following the steps below:
1. Cut the lining paper into strips which measure the length of the wall plus about 25mm (1″) round the corner to the next wall.
2. Use a long spirit level and mark a horizontal line along the wall about 1″ below the first length.
3. Paste the first length and concertina fold it.
4. Working from one corner, gradually open up the folds and smooth the paper down, eliminating air and creases as you go until the other corner is reached, making sure the paper is hung parallel to the pencil line.
5. Make sure all edges are fixed down firmly, applying a little more paste to them if necessary.
6. Successive lengths should be butt jointed (leaving just the slightest gap between the edges), working from ceiling to skirting.
7. Allow lining to dry thoroughly before hanging your wallcovering.