I got an old sheet and measured the size if the double bed or 5 feet bed I have. I bought 6 yards of creep material; in mauve as that is my colour. I halved the 6 yards of creep and joined the lengths. French seem. I then hemmed all around the end and then started to thread a full needle of thread as long as I could manage. I worked all around the material so I could pull each treaded area into little tucks all to fit the 5 feet bed circumference. when I had this material prepared I pined and then tacked the valance material onto the sheet I had prepared in size for the 5 feet bed. the sheet was a single one as you only want the size of the flat top of the mattress as the valance fits under the mattress. the valance must be the height of the base only , this is a valance you leave on under the mattress. hope this helps if not e-mail firstname.lastname@example.org for further info. olive I have this under valance for 20 years and it washes great dose not need ironing as the creep is synthetic.
Quick and easy: https://www.hgtv.com/design/rooms/bedrooms/quick-and-easy-bed-skirt
No sew: https://www.designertrapped.com/no-sew-bedskirt-tutorial/
attach to three sides of a flat sheet the size of the box springs; two long sides and the bottom; select the material of your choice -- allow for 'gathers', box pleats, or just a straight run when you measure for the length; the depth of the panel will be from the TOP of the box spring to the floor; best done with a sewing machine, but you could use a washable fabric glue.
OR if you're not into sewing --- here's a quickfix solution https://homeguides.sfgate.com/make-bed-skirt-out-flat-sheet-97335.html
Linda: Here's an easy one