How to merge multiple pages into one page?

Hi,

I need to develop a plug-in to merge multiple pages into one page using SDK.

1)create a blank Document;

2)create a blank page with desired size;

3)copy content from page 1 to the blank page with a position;

4)copy content from page 2 to the blank page with another position;

5)save and close the document.

Any idea about step 3) and step 4)? Thank you.