This one will be easy, especially if you wanted the BR type.
All of the babies of this cross will be blue, but only the males will have the barring also(white spot on head on chicks).
Keep the best male of your preference and breed him with pure barred rock hens(well, or any barred hen..).. and then there's two ways you can take the next generation:
1) Keep the sons pure for barring- these typically have better defined barring and are lighter overall than the sons with just one barring gene.
OR
2) Keep the blue barred daughters and breed with pure BR rooster.
OR do both.. crossing the sons with pure BR hens.
Then you're set for a pure breeding barred line with blue in it.
For splash barreds, just breed two blue barreds together. These tend to be extremely light..