how do i put words in front of a picture using pages?

Insert your image into Pages and scale to taste. Visit the Arrange menu ▸ Section Masters ▸ Move Objects to Section Master.

Now insert and scale a Text box that you position over the image. Set the font color to an appropriate size and contrast. You can move this Text box to Section Masters too, or not.

Since you did not state the version of Pages, the assumption for the previous and current content is Pages v5.

The previous example that I provided will get you text over an image that will (as an object master) repeat on every page. Probably not something you want in all cases. 😉 The other approach, that will achieve text over image, but not repeat on every page is as follows:

Insert and scale your image. In the Format panel's Arrange tab, choose the object placement that you need, and then set wrap to none. While the image is still selected, from the toolbar, click Text box. This will force the image backward, and the Text box will be on top. Choose the same object placement and wrap setting in the Format Arrange tab. Style your text for visibility over the image, and adjust the Text box size and position. With the Text box still selected, press the shift key and click on the image. With both selected, choose Group from the Arrange tab. Position the image and text to your document need. Done.