This is how it looks wrapped around at this stage.
Now carefully measure 2 bits of bias binding for 2 edges and sew them on.I used half inch and to be honest it was fiddly. I would recommend wider or you could add extra to your fabric and turn the edge over if you aren't confident sewin on bias binding. I also zigzaged the edges to neaten them.
Mark the centre and fold the sides in to the middle right sides together.
Sew the sides together, I used half inch seams.