How should a review be written? I don't understand how to write one.

Writing a review will depend heavily on what kind of material you are reviewing. But no matter what, a review should be more than a simple summary of the material. For a review, you will need to take plenty of notes. You should include some description (for example, if you are reviewing a novel, include basic details about the plot, the time period, the characters, etc.). Talk about what kind of work it is — is it fiction? nonfiction? poetry? A good review should give the reader an idea of how the different pieces of the piece work, how the author's style comes into play. Again, to use the example of a novel, a review should be a critical assessment of the work. What did the work have to say (about social conditions, aesthetic matters, and so forth)? How did the book make you feel? Not only that, but how did the pieces of the book work together to make you feel what you felt? One thing to consider when talking about your personal response is whether it might be commonly held or not. You have to consider your place as a reader and reviewer of the work. Did the work move you? Why, or why not? How does it engage with current society today? Which societies might it engage with? Look at the big picture, but try to avoid generalizing.