Click the 'Edit Selected Page' button on the left menu to begin adding content to your first page
Click the 'Add New Content to Page' button to begin to add images and text to this page by choosing from the options presented to you.
When you click on a section on the page it is surrounded by a green border to indicate the current content block, the editing options for the currently selected block will appear on the left menu under 'Edit Options'
You can remove this help text by selecting it and clicking the 'Delete Selected Content' button.