Methodology section-dissertation

hi
i'm writing my dissertation this year on the power and ifluence of the mass media.
i'm not sure how to write methodology section?
i'm not doing any reasearch for my project, but rather focusing on literature sources.
how should this methodology section look like,what should it include?should be general overview of my sources?or general overview of the theories that i'm going to use?

also how to reference electronic dictionary in the text according to the harvard reference system?for example britannica?