remove the clips as shown in pictures .
check the video
i have uploaded here
removal wagon r alto k10 zen estilo a-star air filter removal - YouTube
fitting back wagon r alto k10 zen estilo a-star air filter fitting back - YouTube
in fitting back is the tricky part
the air filter box has two selves at the intake portion , you need to lift the clips first (use some paper in between clips so it wont disturb you while fitting back
then insert the selves back into place and then lock the clips
then place the box over the bushes holders.