At first I also had trouble getting my head around this module. Heres how I think you should approach it:
The thing to remember that it is primarily a close reading of the text. You need to be extremely familiar with King Lear; in the way you would previously have studied Shakespeare. E.g. plot, themes, context, characters etc. etc.
The other part of the module is to examine how this very text has been read and received in different contexts. Therefore you should select a few different established readings on the text, E.g. Feminism, New Historicism, Marxism, etc. Understand how the play can be perceived and valued in various ways, in accordance with the context in which it is being read/performed, and the prevailing values of a circumstance other than Shakespeares.
To cover the received aspect, view a number of productions of the play, (film or stage) and/or use information from some significant past ones. Try and identify within these productions, how an original text can and has been utilised in other manifestations, and how productions of this text might emphasize the values from some of the aforementioned readings.
Once you have done all this, in order to remind yourself that the actual text itself, King Lear, is really the very essence of the module, try to consider that given the perpetual engangement with the text; if the play is constantly subjected to criticism and analysis, and if there are always contentious directorial considerations evident when appropriating the text, does this give further meaning to the original text, and ensure its posterity, or to use the syllabus jargon, grant it textual integrity?
Good luck!!