In version 5.2 of Apple's Pages app for OS X (Mavericks), how do I change the page layout?
Note the 'DOCUMENT' icon at the far right of the very top of the document. Click on the Document Icon ... You will see a formatting screen similar to the 'older' inspector. The margin details are below "Document Body"

You need to select text in the body and then change the Document left margin from 2.69 inches to 1 inch.

Also, you might need to remove the left items. Depending on how thorough you want to be, update the body style to match the new definition, but at that point once the left margin is something more sane like 1" - you can fix your indents if desired by dragging the tab stops in the ruler.