I used what's known as the Paleh method for breeding blue roses via the picture guide created by /u/Peach-n-Key.

The first person interested will get five pairs of the orange and white roses pictures on the left side of the image. These breed special roses roses which yield blue roses. If you're looking at the picture guide, these are the orange (RED star) and white (BLUE star) roses.

The second person interested will get five pairs of the red and white flowers shown below me in the image :) These breed the orange roses which can then be bred with the existing white roses to produce special red roses. If you're looking at the picture guide, these are the white (BLUE star) and red (BLUE star) roses.

The third person to express interest will get the 2 purple roses in the middle of the image as well as the 2 black roses to the right of the yellow roses. The purple roses bred together breed the white (BLUE star) roses. Those white roses can be bred with the black roses to produce the red (BLUE star) roses. If you're looking at the picture guide, these are the purple (YELLOW star) and black (GREEN star) roses.

And last but not least, the fourth person to express interest will get the two pairs of purple and white roses pictured on the right. If you're looking at the picture guide, these are the purple (GREEN star) and white (YELLOW star) roses.

That, or let me know if there's a particular point in the process at which you'd like to get started. Consider these easy, medium, hard, and extra hard starting kits for breeding blue roses :)