fabric size of
80cm x 10cm

Your necklace will look better if it had a pattern on it

sew the hems (to neaten it up)

and sew the longer sides together
so it is like a hallow tube

insert wool batting into the the "hole"
and move it so it is in the middle of the baric

so it should look something like this...

using a black platic elastic
you tie it around the two ends so the fabric ball does not loosed

and keep repeating so it looks something like this

and then sew on ribbon on the ends

or if your you can use a longer fabric and just sew the ends together