A very simple example (without error handling and such) would be:
use Net::Twitter;
my $nt = Net::Twitter->new(
traits => [qw/API::RESTv1_1/],
consumer_key => "Consumer Key (API Key)",
consumer_secret => "Consumer Secret (API Secret)",
access_token => "Access Token",
access_token_secret => "Access Token Secret",
);
my $statuses = $nt->user_timeline({ count => 1 });
print "Latest Tweet: $$statuses[0]->{created_at}\n";
print "Latest Tweet ID: $$statuses[0]->{id_str}\n";