Lay drapes face up on your work surface. Smooth out all wrinkles by hand or iron fabric flat. If you have made lined drapes, attach lining to the header before attaching tape.
Cut the pleater tape into lengths for each curtain, allowing an extra inch for each header beyond the width of the fabric to avoid having to tack down raw tape edges. If your tape has strings that you will need to pull, you may need to leave the ends open until you finish pleating; check package directions for exact instructions or consult the information sheet from your sewing center.
Pin or baste the pleater tape face down to the top of the face-up curtain, allowing 1/4 inch seam allowance. Attach the tape, using a sewing machine or needle and thread. Turn the curtain face down, folding the tape over the seam. The tape will now be face up.
Pin and sew the bottom edge of the pleater tape to the curtain. You have now made a header and are ready to begin the pleating part of your work.
Purchase tape and multi-prong hangers based on the width of your curtains and the depth of pleats you want. Hangers come in three- and four-pronged models and tapes also allow for pleats of several depths.
Turn under, pin and stitch the raw ends of the tape as soon as you have attached the tape to the curtain fabric.
Insert pronged hooks so that they fill the tape pockets completely, rather than leaving partially empty slots at the top edge of the curtain. Insert a single hook at each end of the curtain unless pronged hooks have used up all the tape. Lock hooks in place, if lockable, and hang drapes.
Investigate curtain width requirements for the header look you want. Some tapes gather curtains twice the width of windows; others gather three widths or even more.
Attach the tape according to directions. Some tapes need to be sewn top and bottom; others need several rows of stitching to function properly. Leave the ends of the tape open until you are sure you no longer need to reach any pull strings that would be covered by tucking and stitching tape ends.
Pull strings according to directions. If you have several rows of strings, it may be helpful to check your progress by turning curtains face up several times to check your work.
Turn in and stitch any raw tape ends. Insert curtain hooks and hang.