Take a reference (ie. make $aref a reference of @a):

my $aref = \@a;
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Extract one element from the array ref by using -> deref operator:

my $thing = $aref->[0];
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Use the array circumfix operator to dereference the whole array ref at once:

my @b = @{$aref}; # used in loops, too
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I've proposed part of my reference howto as a tutorial here on PM. It may further help your understanding: Tutorial RFC: Guide to Perl references, Part 1.