You need Maven 3 (at least 3.0.4) and Java 8 or later to build Tobago.
In the project directory you can use:
to run the install target on all sub projects. This will put all necessary artifacts into your local repository.
Switch to sub-directory and call Maven to run the demo:
cd tobago-example/tobago-example-demo mvn jetty:run
Browse to the local URL http://localhost:8080/tobago-example-demo/