Copy all white paths from 'base paths' layer and paste it in a new layer. If you want, you can just duplicate the 'base paths' layer. Now use the Type tool to type in your text message and send it to back (note: your text must be sit below the shape). Then select the text object and the shirt path, go to Object > Envelope Distort > Make with Top Object or press Ctrl+Alt+C. This will distort the text with the selected shape.