WARNING: This page is about a different car, the 2012 Subaru Outback and 2012 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Install the bumper face so that the under cover front end (b) comes inside the front bumper face (a).
Fig 1: Identifying Proper And Improper Bumper Installation Position
Courtesy of SUBARU OF AMERICA, INC.
Install each part in the reverse order of removal.