For the design you need 13 squares - mine were 11cm by 11cm. The layout is as follows:
So corresponding colors should be match and there are three squares that are folded in half to connect the front and the back.
For the squares I used the granny square pattern that I found on Rose Hip. I understand from friends that they find it difficult to crochet 3D flowers and especially figure it out from the desciptions. Therefor I made a small tutorial.
As I do not like to put all the squares together at the end, I joined them as I went. On attic 24 is a very clear tutorial on how you can join squares on the go.
For the handles I made a chain of 84 stitches (beige), on the second row (turning) I repeated 4 chains, 1 triple crochet in each 5th chain of the first row. This made the 'ladder' for my ribbon. Then I used orange for the sides: 3 double crochets in the TC of the beige and then 1 single crochet around the 4 chain spaces.
Finally, for the lining I combined two tutorials. It was very helpful to sew in the lining while the bag was inside out like was suggested in the tutorial on While they play. Further I found the tutorial of Future Girl very clear.