./asadmin start-domain yourdomain
./asadmin create-jvm-options "-javaagent\:/path/to/plumbr.jar -agentpath\:/PLUMBR_HOME/lib/linux/32/libplumbr.so"
or
./asadmin create-jvm-options "-javaagent\:/path/to/plumbr.jar -agentpath\:/PLUMBR_HOME/lib/linux/64/libplumbr.so"
./asadmin restart-domain yourdomain

When everything went smoothly, you will see the following banner in the restarted JVM standard output and a new JVM appears in https://portal.plumbr.eu.

************************************************************
* Plumbr (15.01.4138) is attached.                         *
*                                                          *
* Plumbr agent is connected to the Plumbr Server.          *
* Open up https://portal.plumbr.eu to follow its progress. *
************************************************************