Welcome to TalkGraphics

Ungroup the header photo. Select the photo of the woman and then select the Fill Tool. From the drop down list of Fill Types on the Infobar select Flat. Now the photo is a solid filled shape.

Hold down the Shift key and drag and drop a photo from the desktop, or Windows Explorer, or the Bitmap Gallery onto the shape.

For the text on the three pop up photos. The text and photo are on pop up layers. Look in the Page and Layout Gallery and you will see the pop up layers.