Your introduction can be longer than 1-2 pages but it needs to be focused. The writing style should be descriptive and argumentative but it is not the place for critical analysis (that goes in your literature review).
It should start from a broad perspective and engage your reader, assuming that they are a non-specialist. This is often called the background.
The background should move you towards your statement of your aim. Once you start narrowing down towards your aim you can start a new section called Problem Statement. The conclusion of this section will essentially be your aim. You should be answering the question: why is this research interesting/important?
You should then state your article m and your research question(s) and your objectives. You can also discuss limitations, but this is optional.
Finally I would suggest outlining the contents of the remaining chapters of your thesis.
The answer depends on the discipline. There are different rules depending upon the the discipline, there is no clear-cut "truth", but there are traditions.The introduction of a literary thesis will not follow the same rules as one in sciences.
Look how other Ph.D. candidates wrote, in your department, in your discipline.