OK, very briefly (and this is for my subject, another social science so it may not apply to yours)
A literature review should be critical - you are examining the strength of the authors' arguments. So, take a theme that they have all written about and structure it something like this…
A says that…. but B disagrees with it because……. However it should be noted that B may be biased because….. C supports and develops A's argument by suggesting that…… More recently, however, D has shown that B's point of view may be valid because…….
Then choose another theme and work that through in the same way.
I would suggest that four articles is a bit limited for this at Masters level - we were always told that if you only stick to the suggested readings, you're only going to get a Pass. It's worth having a look at the articles cited in your selected articles and see if they can add anything to your argument. And background reading is always good especially if the subject is new to you.
This is a very very basic explanation of how to structure your lit review, and others may disagree, but I hope it's given you somewhere to start.