I sewed the two legs separately and then put one inside the other to join them together (a top tip passed down from my mother).
Then I folded over the fabric twice and ironed it in place. Finally, I sewed around the edge near the bottom of the turn over. This could be a place to top stich with a double needle if you have one.
To thread the ribbon through, attach it to a safety pin first: this is easier to find and push through all the fabric!
Et Voila! A beautiful pair of pyjamas with no visible seams or hems! Hope she likes them!