If they can detect gravity waves at several separated sites around earth, and if gravity waves propagate at a finite speed, they should be able to see where the gravity wave came from in a general sense. If they detect the gravity wave at 4 sites not coplanar they should be able to narrow down the direction in spherical space. I don't know what angular resolution they expect.
The next step is to arrange detectors and use the differences in signal at different ones to map out what waves you are receiving, where and when. But it is obviously much harder to get a good picture of a one-off, transient phenomenon that way, than a picture of a steady source.
Strong gravitational waves are easier to imagine getting produced in a transient rather than a continual source. Gravity tends to rapidly smush things into symmetric shapes that thereafter produce uniform gravity, and only changes in gravity produce gravitational waves. A gravity wave is a propogating "ripple" in space-time itself.
The wildcard is that we know that our theory of gravity probably leaves something out, in details. There is no consistent quantum theory of gravity. We only know our gravity theory checks out for large scale phenomenon. But wave -propagation- may depend in some respects on small scale phenomenon.
Mathematically, they integrate a bunch of infinitessimals without really knowing how the infinitessimal scale looks. For large scale and continuous enough properties, that has always worked so far. But supposedly sensitive gravity wave detectors have been around for a while now, and nobody has actually seen one with them, to date.
The detection schemes are getting better, and obviously as the article shows they have high hopes. We shall see, and that is always fun...