basically a literature review is a compilation of key sources that you are going to use in your discussion. For your investigation you might use academic journals, essays, maybe bbc articles and news reports. Choose a couple of good sources that will help your write your discussion and in the literature review, you have to evaluate them. This means that you have to discuss why this source is useful for your investigation and whether it is reliable or not, if it's biased, the perspective of the source etc.
You can write a paragraph or a couple of paragraphs for each.
A really good literature review will connect the sources together and compare it to eachother as well as discuss why they are useful to use together.