DNA is used to build proteins in ribosomes. The DNA is used as a blueprint along with messenger RNA in the transcription phase. The DNA, which is normally a spiral double-helix configuration, unwinds and splits along the paired base "rungs" of the ladder, providing an open interface the mRNA can match to. Once the correct order has been established by transcrioption, the mRNA moves into the cytoplasm of the cell to pick up the correct amino acids, which are the building blocks of protein.
The translation part of the process occurs as the mRNA drops off the amino acids in the correct order, which was provided by the DNA template. The amino acids are assembled through the ribosome in the correct order, which produces protein identical to the DNA copy from the original double helix strand. The proteins are then distributed where they are needed in the cell.