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Arrays are ordered, zero-indexed:

my @nums = (3, 1, 4, 1, 5, 9, 2, 6);
print $nums[0], "\n";        # 3 — note the $ sigil!
print scalar @nums, "\n";    # 8 (length)

push @nums, 5;               # append
unshift @nums, 0;            # prepend
my $last = pop @nums;        # remove and return last
my $first = shift @nums;     # remove and return first

my @sorted = sort { $a <=> $b } @nums;     # numeric sort
my @reversed = reverse @nums;

Sigil-changing magic: @nums is the whole array, but $nums[0] is one element (it's a scalar, so use $). This trips everyone up at first.

@_ is the implicit argument array inside a function:

sub greet {
    my ($name) = @_;
    print "Hello, $name!\n";
}

Slices:

my @nums = (10, 20, 30, 40, 50);
my @two = @nums[1, 3];        # (20, 40) — note @ sigil for multiple