then i decided on doing four sections instead of loads, so i did a running stitch all the way along and made ruffleds sections along the sheet.
like this, this is with just two and a half sections sections
and then it should look like this. you can do as many sections as you like the anthropologie one has quite a few.
then i used the sewing machine to secure it in place, and then unpicked the running stitch.
and its done, i did think about adding more sections, but i left it like this for now.