Gene expression, or DNA translation is how out genes produce the proteins that they code for.
DNA, Deoxyribose nucleic acid, is like a man at the control desk of the cell.It is made of 4 bases, Adenine which binds to Thymine and Guanine which binds to cytosine.
In order for gene expression, these bases are unzipped by an enzyme called helicase.
This allows transcription to RNA, ribose nucleic acid. RNA bases to line up against the DNA. It's called transcription because it's in the same language of nucleic acid.
Then the RNA is translated into a different language, the language of protein.
These proteins then go on and do all the interesting processes of the cell. It makes us do all the things we do and makes us look and act differently.