How to do RMAN archival backup?

rman target / nocatalog
configure controlfile autobackup on;
run{
 allocate channel d1 type 'sbt_tape';
 backup current controlfile;
 BACKUP ARCHIVELOG ALL NOT BACKED UP 2 TIMES;
 DELETE ARCHIVELOG ALL BACKED UP 2 TIMES TO DEVICE TYPE 'sbt_tape';
 crosscheck archivelog all;
 release channel d1;
}