Measure the width of the bed between the posts at the foot of the bed. Measure from the tops of the posts to the ground and multiply this measurement by two. Add this measurement to the bed width measurement and add 12 inches to the total number to account for sag.
Acquire four panels of sheer fabric at the determined measurement. Drape two of the panels over the top of the bed poster frame, overlapping the panels slightly in the middle and arranging them so they overhang equally on both sides of the bed.
Drape one panel over the frame connecting the posts at the foot of the bed. Drape the fourth panel over the frame at the head of the bed. Adjust the panels so they hang down an equal distance on each side of the frame.
Pull the front portion of the foot panel toward the left pole and tie it in place with a matching curtain tieback. Pull the back portion of the panel to the right pole and tie it in place. Repeat for the panel at the head of the bed, if desired, or leave the panels hanging flat behind the headboard.
Separate the side panels at the split where the two lengths of fabric overlap. Pull the panel to the corresponding post and tie it with a curtain tieback. Adjust the panels and ties.