Google "How to Tie Your Boat to a Cleat Hitch Easily and Quickly" for a short video which illustrates this technique (and shows what I mean by a "Boat Cleat") far more succinctly than my written attempt.

I was going to ask the Op of this comment thread/others what ~ given the narrow width of wallpaper ~ how one pieces them together to cover a large window?

I make FABRIC window coverings VERY INEXPENSIVELY by hunting for beautiful fabric discounted during annual sales. Even high-end designer stores will HEAVILY DISCOUNT exquisitely beautiful HIGH QUALITY fabrics (Brocades, silks, chintz, satin, damask, laces, velvets, cottons, linens blends, etc.) passementerie (decorative trimming such as bullion fringe/lengths of tassels or fringe corded piping used on furniture and clothing [e.g. Military Uniforms), upholstery fabric and TAPESTRY fabrics.

There are products which facilitate "no-sew" options but I encourage you to buy a used sewing machine (I started on a free antique treadle machine which had seen better days & refinished it into a showpiece), or a modern BASIC machine [new or used].

Sewing a straight (or curved) line is NOT DIFFICULT with a little practice…if a used machine is too dear…one can learn to hand sew seams which are so perfect one can not distinguish them from machine stitching.

My girlfriend's hand stitching is blazingly fast and perfection, itself.

I began sewing my own home "decor" items (pillows/fitted piped & pieced futon covers/window treatments when becoming APPALLED at the DUBIOUS "quality" UNLINED "Custom Drapes" inherited when we purchased a house. The inflated costs were ASTRONOMICAL and the "craftsmanship" so LAUGHABLY lacking that I knew I could do better.

A high end antiques dealer, the best upholsterer I have evee seen and a designer each tried to HIRE me upon seeing the quality of my finished product. This waa not due to any tallent on my part but rather simply practice and dogged detetmination. Also I ENJOY creating such items and the huge financial savings, so the process itself is a joy to me.

You will feel genuine PRIDE when you realize how EASY it is to create home decorating items which possess FAR HIGHER WORKMANSHIP than high-end creations at a FRACTION of the cost.

A window covering LOOKS MORE EXPENSIVE if you use volumes of a cheaper fabric than if you SKIMP on the AMOUNT of far more exoensive fabric.

Oh we RENTED for DECADES before we could AFFORD to buy…so I made VERY LONG CURTAINS adding volumes of (cheap) fabric such that my window coverings would generously cover a far bigger window….and took them to the new rentals.

Landlords tried to BUY my window coverings if ever they saw my interiors (which I discouraged as they invariably DOUBLED or TRIPLED my rent as I utterly tranformed the generic, neglected suites with paint and fabrics). We simply gave notice and moved…taking the "upgrades" with us…much to the dismay of the new renters.

Good luck, all❤