Here is some actual working code from SetDB 0.2:
use strict;
use DBI;
use SetDB;

Must turn off no strict subs so I can use magical barewords

This is certainly not required for using this module

no strict 'subs';

Okay, first we set up our DBI connection

my $dbi = DBI->connect(
'DBI:mysql:database=setdb_test;host=localhost', 'setdb', 'setdb');

Now we set up our schema

use vars qw( $schema );
do 'schema.pl';

This creates our SetDB database

my $db = new SetDB($dbi, $schema);

Lets get a set of people and their books

my $people = $db->newSet(person, book);

Now loop through and print out each person

while(my $person = $people->fetchNext())
{
print "Name: $person->{name}\n";

This is the set of books which that person has

my $books = $person->{book};

Lets go ahead and print all of their books

while(my $book = $books->fetchNext())
{
print " Book: $book->{title}\n";

# Demonstrate updates by adding ' sucks!' to the book's title
$book->{title} .= ' sucks!';

}
}