How does DNA make proteins?
First the transcription process copies a segment of DNA into mRNA by using transcription factors that recruit or block RNA polymerase, which binds to protomotor regions on DNA and code it into a complimentary strand of mRNA.
Second, mature mRNA, lacking non-coding sections, leaves the nucleus and attaches to a ribosome.
Third, tRNA delivers the amino acid specified by the 3 nucleotide bases (codons) to the appropriate site on the mRNA.
Fourth, and finally, the next amino acid is delivered to the ribosome and peptide bonds are formed.