Import this schematic into your world,
and rename the color that you want to build out of.
For EXAMPLE: Orange.
Then put it in your off hand.
And just jump to build up,
sneak and peak out of the side of your block to build the concrete next to the block you are standing,
finish building?Well just put it back to the main hotbar and it will stop building!

Still Confused?

Follow the Screenshots Steeps and you are good to go