The content of a text is the meaning its words contain. Meaning in many texts - especially poetry and fictional texts - often operates at more than one 'level'. There can be a 'surface level' of meaning and 'deeper levels' of meaning.
An important essay writing skill is to be able to reduce the content of a text down to just a couple of sentences. Done effectively, a short summary that tells both what a text is about and why it was written can be a very impressive opening to an essay because it immediately suggests in a succinct way that you have understood the text really well and have internally absorbed its meaning and purpose.
Having given this 'overview', you can then get on with what gains most marks - a discussion of the effects of the text and how these build up into an effective structure along with a comment on methods and reasons.