If you want to develop for ODTN you should first get ONOS . Please follow the instructions in the following link to setup development environment for ONOS:
And the following link describes a simple "local" workflow where you build and run ONOS on a single development machine.
Note 1: For ODTN development purposes you should checkout master branch.
Note 2: Before launching ONOS please export these apps:
ONOS_APPS
$> export ONOS_APPS=odtn-service,roadm,gui2
Then you can follow one of these guides to setup a phase 1.0 demo as a base: