Weave in all ends. Pull out provisional co and place stitches on spare needle. If you plan to add an elastic into the casing, get your elastic and measure it out so that it is snug but not too tight, about 2”/5cm below your natural waist. Sew the elastic ends together and position in place.
and the crotch further.
Finally, the legs are worked individually in the round, and completed
with a short ruffle and contrasting picot bind-off.