The majority of genes are expressed as the proteins they encode. The process occurs in two steps:
Transcription = DNA → RNA
Translation = RNA → protein
Taken together, they make up the "central dogma" of biology: DNA → RNA → protein.
Here is an overview.
This page examines the first step:
Gene Transcription: DNA → RNA
DNA serves as the template for the synthesis of RNA much as it does for its own replication.
Some 50 different protein transcription factors bind to promoter sites, usually on the 5′ side of the gene to be transcribed. [View more details]
An enzyme, an RNA polymerase, binds to the complex of transcription factors.