First edit your /etc/oratab changing N to Y like that:
Must be change to Y:
Then to start you must use the dbstart script like that:
su oracle -c "$ORACLE_HOME/bin/dbstart $ORACLE_HOME"
Where "oracle" in the "su" command is the name of the user you used to install oracle.
This will up all oracle essential services including the https port 1158 (and you can put that in an auto-start script)
And to stop it:
su oracle -c "$ORACLE_HOME/bin/dbshut $ORACLE_HOME"
And to backup it (dump) ;-)
$ORACLE_HOME/bin/exp full=y mybackup.dmp
Remember to test your backup before thinking its working.