The layout details for the default page template and page template one  is as follows:

1. The main input area is on the left side of the page. It is approximately 66% of the width of the page.
2. The sidebar is on the right side of the page. It is approximately 33% of the width of the page. In WordPress the sidebar is where “widgets” go. It is sometimes refereed to as the “widget area.”
3. You enter text/images in the sidebar (widget area) from the Dashboard/Appearance/Widgets page. Look for the sidebar that corresponds to the page template. You can enter as many widgets as you want in a sidebar.