Select your text box so that the text toolbar appears (where you change the font, size, alignment, etc). On that toolbar is a white box with a down arrow next to it. Click the white box to choose from a selection of colors or the arrow to create a more customized color. If you want to match a color that you're already using in your background somewhere, click the arrow and use the eye-dropper tool to select the color.

You're right, color sets are not used for standard menu text. Color sets are used for button highlights and for subtitle text.

Rob