#!/usr/bin/perl --
use strict; use warnings;
use CGI::Application;
use CGI::FormBuilder;

Main( @ARGV );
exit( 0 );

sub Main {
    MyAppname->new->run;
}
BEGIN {
    package MyAppname;
    use parent 'CGI::Application';
    use CGI::Application::Plugin::AutoRunmode;
    use CGI::Application::Plugin::DebugScreen;
    
    sub What : Runmode {
        CGI::FormBuilder->new->render;
    }
    sub Edit : Runmode {
        ...
    }
    
    sub View: StartRunmode {
        my ( $cgiapp ) = @_;
        my $form = CGI::FormBuilder->new(
            method => 'post',
            fields => [qw( one two three )],
            params => $cgiapp->query, # get CGI params
        );
        
        
        if ($form->submitted && $form->validate) {
# you don't print in CGI::Application
            return $form->confirm;
        } else {
            return $form->render;
        }
    }
}