By the end of Month 6, the student should submit a literature review of the agreed research area to the principal supervisor, who will provide feedback.
The course notes for the MSc "Informatics Research
Review" course has some notes on the form and content of a literature
review and how to go about tracking down relevant publications.
However note that the literature review referred to in the IRR notes is in preparation for an MSc project. Consequently, the suggestion there that reading 3-4 papers in depth will suffice and that the review will be about 3000 words long are both almost certainly underestimates as preparation for PhD-level research.