The first paragraph of your essay is the Introduction Paragraph. An Introduction Paragraph has the following sentences in order: 

1. Hook Sentence – this sentence interests the reader and is related to the main idea / topic / theme of your essay

2. Bridge Sentence – this sentence connects the Hook Sentence with your Background Information 

3. Background Information – these sentences (usually 2 -4 in total) answer the questions of Who, What, Where, When and Why and the background provides context to the reader including information about your main idea, an explanation of the topic and vital details about the work (novel, poem, play, etc.) your are referencing

4. Thesis Statement – this sentence should state your opinion (what), main arguments (how) and why should the reader care about your opinion (so what)