Question abouit libmail-spf-query-perl

[Alejandro Facultad]

Dear Debian Perl Group,

I'm a mail, administartor using Debian Etch + Postfix 2.3.8 mainly, and 
I've installed SPF check with:

apt-get install libmail-spf-query-perl

But after installation I have no idea how to configure the package to 
start SPF checks, and Google doesn't tell me anything about that.

Please can you tell me wath to do after install libmail-spf-query-perl 
in order to enable SPF ???

Really thanks

Alejandro