To make it you will need:
Cut two lengths of cord approx 12" or 30cm, seal the ends either with nail varnish or a flame and fold in half. I've got much braver with this stuff the more I use it and just carefully melt the ends in the flame of the gas hob now.
Line your button holes up carefully so the buttons stay lined up nicely.
Now add a tassel. This was a bit fiddly, there might be a better way, but this is how I did it.
I pulled it down neatly to cover the knot and then tied it with another short piece of cord.
Then I just trimmed the ends of the short cord close to the super glue.
Then I chopped the bottom of the tassel so all the cords were level. To finish off I sealed the ends of the tassel by melting them quickly in a flame.