In its default state (where no "regions" or "layouts" are defined), it should look and behave similarly to (and eventually the same as) the "classic" Topology view.
Note that this view is currently "experimental", although the longer term plan is to bring it up to par with the "classic" view, which it will eventually replace.
A more detailed description of the current state of Topology 2 can be found HERE. (Steven to provide link)
Notes on <scale>, <offset-x>, <offset-y> values:
onos> layouts id=lDE, bgref=@europe, region=rDE, parent=root id=lES, bgref=@europe, region=rES, parent=root id=lFR, bgref=@europe, region=rFR, parent=root id=lIT, bgref=@europe, region=rIT, parent=root id=lMilan, bgref=+segmentRoutingTwo, region=rMilan, parent=lIT id=lUK, bgref=@europe, region=rUK, parent=root id=root, bgref=@europe, region=(root), parent=root
Putting this all together
Topology Overlay API