If you are making templates to cut, then sew the pieces together I would sew in this order (I hope I have the piece names/numbers correct)
D1, E1, and B2 - sew this unit together
F1, C2 and H1 - sew this unit together
I2 and J1 sew this unit together
Sew G1 to the F1, C2 and H1 unit
Sew the D1, E1 B2 unit to the floral unit
Sew the I2, J1 unit to the other side of the floral unit
Sew the floral unit to the F1, C2, H1, G1 unit
Some folks mentioned paper piecing, and you can do that IF you straighten out those curved lines in F1, C2 and the floral unit. If you do this, paper piece it in the same order as above.