Add a Background Color

Click Format on the main menu bar.

A drop-down menu will appear.

Select Background from the drop down menu.

The Background dialog box appears.

Click on the text box inside of the background fill window.

A drop-down menu appears with color options, more colors, and fill effects.

Select more colors (as in graphic 1).

The Colors dialog box appears (as in graphic 2).

Select a color from the color wheel, and then click OK.

The color that you have selected (in this case, pale yellow) will now be the background color.

Click on apply to all button.

The color that you have selected will now be the background color for all of the slides, as in graphic 1 below. The slide (and all future slides that you create) will be colored this color, as shown in graphic 2 below.

You can repeat this process at any time to change the color of any single slide -- or all of the slides -- to another color.