'->' is the dereference operator.

$foo->[0] is dereferencing an arrayref
$foo->{bar} is dereferencing a hashref
$foo->(@blah) is dereferencing (and invoking) a function-ref
$foo->bar is calling the method "bar" that is defined in the class tha
+t $foo has been [bless]'ed into.
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The first line you don't understand is creating a new instance of the class HTML::TokeParser. new() is, by common convention, the method that returns a new instance of a class.

The second line is an if-else statement. It can be rewritten as such:

my $text_index;
if ($token->[0] eq 'T') {
    $text_index = 1;
} else {
    $text_index = -1;
}
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Once you understand that $token->[0] is treating $token as a reference to an array and is getting the zero-th element, the other two parts shouldn't be that hard.

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.