How do I start the introduction to an analysis paper?

An introduction to a literary analysis contains many of the same elements as the introduction to other kinds of essays, particularly the argumentative essay.  Remember, an analysis is making an argument that you are going to support with the literary text.  Let's go over what you need, generally and specifically. 
First, a good way to start is the funnel method, starting with a general idea and then narrowing down to the specifics of your argument, as a funnel is broad at the top and narrow at the bottom.  For instance, if I were writing an analysis of The Great Gatsby (Fitzgerald), I might begin with some discussion of the American dream.  Or I could begin with some discussion of the Roaring Twenties, depending on the focus I am going to narrow down to.  The idea is to engage the reader in a more general topic as a way of opening the door to your analysis.
Second, you must name your literary text and its author in the introduction. We do not assume the reader is our professor, who already knows the text.  You can do this after you make some more general statements.  It is not necessary to do this in your very first sentence.
Third, it is a good idea to give a very brief overview of the literary text.  You often have to be a bit selective, and you need to bear in mind what you are going to focus on in your analysis. For example, a book might have many characters, but you are not necessarily going to name all of them if they have no place in your discussion. As a general matter, letting the reader know the setting, the main characters, and a few words about the plot is enough.  I might say about The Great Gatsby that it takes place in the 1920s in New York, features Nick as a narrator, and features the Buchanans and the Wilsons as contrasting couples.  Again, what I choose to focus on in my brief overview will depend on what I am going to focus on in my analysis.
Finally, you need a thesis statement, just as you do for most essays.  What is the main idea you want the reader to take away after reading your essay?  How will you support that idea? Both of these must be in the thesis statement.  In a literary analysis, your support is going to be the text, and you are expected to be examining the literary elements of the text, such as imagery, tone, setting, and characterization.  So, returning to The Great Gatsby again, I could have this as a thesis statement:

Fitzgerald's settings, characterizations, and contrasts show us that the American dream is always receding, never to be realized. 

Once you put all of this together, your drawing in part, your naming of the author and the text, your brief overview, and your thesis statement, you will have a fine introduction.