Stuck at blast in Bio perl

[bio_informatics]

Hi All,
I am newbie in bio perl.
I want to blast a sequence using, standAloneBlast and parse its output later.
I have my blast+ installed and has been added to PATH.

Now, here is the mystery.
How do I proceed? What should be done?
I have browsed many posts but was unable to understand how and what they are doing

my $in = Bio::SeqIO->new (-format=>'blast',-file=>$fasta_file);

what this will lead me to?
Next I tried

while(my $result= $in->next_result){
      ##I cannot get next_result
}

OS: Ubuntu 12.04
However, on command line, we build database by running a sequence against another file or database, and then blast is run.
How is the case in Bio Perl?

Please help me understand this.