You've got a pile of answers already, but here's one more!

Here's a hash:

my %hash = ( a => 1, b => 2 );
print $hash{'b'};  # prints 2
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And here's a hashref, which is like the one that you had:

my $hashref = { c => 3, d => 4 };
print $hashref->{c};  # prints 3
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As you can see, you use percent and brackets to define a hash, and dollar and braces to define a hashref.

In addition, you can get a reference to something by putting a backslash in front of it ..

my $ref_to_hash = \%hash;
print $ref_to_hash->{'a'};  # prints 1
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References are useful when you want to pass data structures around -- it's more efficient to pass a reference (that big thing over there) rather than the structure itself.