BACKGROUND GRAPHICS
Check Omit background graphics from master unless you want to include the background image on each slide.
Click on the color dropdown, which will popup to Fill Effects.
More effects include backgrounds, gradients, and patterns!

We are going to add in a photograph (or graphic) as a background.
Click on Picture. Browse to find the picture.
Select picture. Now we see a preview. Looks terrible! We will need to move our text boxes around, change font, etc.
Click Apply to save background.
Move your text boxes around and change your font colors as desired.
Next, we will give the title box a background color to make it stand out more.