#11, those are Top hooks..

you just need a hook on the bike near the wheel to hook your bungee /shock cord over.

then you pull against the elastic tension to bring the bags top hooks over the racks top rail.

alternatively , loosen one end of the Bungee from the Bag, pass a steel ring over it ,
and re attach the cord.

then you hook the ring over the frame mount,
It can be a collection of a bolt and a nut and a flatwasher to hook that ring over.

A guitar strap button would make a tidy way
to make a bottom anchor, on the frame.

At the racks bottom there are height adjustment bolts , a natural place to add a hook for a pannier lower tie down.