Pontiac 2010 Vibe Owner's Manual page 70

2-50 Seats and Restraints
If the position you are using
does not have a headrest or
head restraint and you are
using a dual tether, route the
tether over the seatback.
If the position you are using
has an adjustable headrest
or head restraint and you are
using a dual tether, route the
tether around the headrest or
head restraint.
If the position you are using
has an adjustable headrest
or head restraint and you
are using a single tether,
raise the headrest or head
restraint and route the tether
under the headrest or head
restraint and in between the
headrest or head restraint
posts.
3. Push and pull the child restraint
in different directions to be sure
it is secure.