Adding additional listeners - ODA -X7

Hi

we have a brand new X7-2M  ODA  (bare metal single node)and we have the database up and running

We need to add additional listeners (listening on port other than 1521) so that clients can connect to the database using those listeners

Is there any special method we need to follow to do that in ODA? or can we just add static listener entries in listener.ora?

If all we need to do is to add static entries for the listeners,we assume we need to do it under $GRID_HOME and not under $ORACLE_HOME. Correct?

Thanks