The Two Step Flow theory suggests that the flow of communication goes from the mass media to influencers/opinion leaders, then to the general public. This is because the theory suggests the public is more likely to be influenced by other people rather than media companies. This means firms target influencers and celebrities in order to target a wider audience.
This theory ties into the Uses and Gratifications theory and the idea of identification, where people use media to look up to people and see themselves in them, which can serve as proof for this theory and why the general public and a bigger audience is more likely to listen to opinion leaders rather than big media companies or conglomerates.