Using RMAN on two node Solaris x86 with Oracle RAC 10g Enterprise Edition Release 10.2.0.3.0

Hello,
Maybe you can help me (new on RMAN backup) in doing this.

I have configured a single Oracle 10g database to have backup with RMAN with following steps:
1.  $ mkdir $ORACLE_BASE/rman_scripts
2.  $ mkdir $ORACLE_BASE/logs   
3.  $ mkdir $ORACLE_BASE/tracking 
4.  $ mkdir $ORACLE_BASE/c_backup
5.  $ sqlplus sys/<password> as sysdba 
6.  SQL> alter system set db_recovery_file_dest_size = 50G scope=both; 
7.  SQL> alter system set db_recovery_file_dest='${ ORACLE_BASE}/flash_recovery_ area' scope=both;
8. SQL> alter system set log_archive_dest_10='location= use_db_recovery_file_dest'; 
9. SQL> shutdown immediate
10. SQL> startup nomount
11. SQL> alter database archivelog;