Once ONOS is installed and running, you can start interacting with it through different interfaces.
CLI
The ONOS CLI is the primary user interface of the platform. It is useful and easy to use, and it allows to run the majority of the commands usually needed.
From the target machine
/opt/onos/bin/onos
More info about how to use the ONOS CLI can be found here.
GUI
ONOS has a GUI that can be accessed through the IP address of the target machine, from any browser. The ONOS UI must be accessed
http://XX.YY.WW.ZZ:8181/onos/ui/index.html
where XX.YY.WW.ZZ is the IP address of your target machine. The default username and password is onos / rocks.
More information about how to use the ONOS GUI can be found here.
This is just a place to start. Look at the following guides to to learn how to interact with ONOS!