A bracket appears at the beginning of the type, at the end of the path, and at the midpoint between the start and end brackets.
To move text along the path, drag the center bracket along the path. Hold down Ctrl (Windows) or Command (Mac OS) to prevent the type from flipping to the other side of the path.
To flip the direction of text along a path, drag the bracket across the path. Alternatively, choose Type > Type On A Path > Type On A Path Options, select Flip, and click OK.
For a video on creating type on a path, see www.adobe.com/go/vid0046.