Configuring pigeonhole/sieve

[Timothy Murphy]

I've been trying for a few days to get pigeonhole/sieve working
in order to filter email with spamassassin.
Unfortunately I have had no success;
and I have found no document which simply tells me
what changes I need to make to which files,
and what other action I have to take.

I'm running CentOS-7 on my home-server, and have postfix + dovecot
working perfectly; moreover spam is marked with ***Spam***
added to the Subject header.
The only problem is that this spam is getting through to my inbox.

It's clear that I'm overlooking some action I should be taking,
and I'm sure there must be a document somewhere
that gives simple and complete instructions
on setting up pigeonhole/sieve to work with SpamAssassin.
If anyone knows of such a document I should be eternally grateful.

I was told at one point that
"You need to pass your mail through dovecot-lda or lmtp",
but I have no idea what this means.
I see in /var/log/dovecot when I re-start dovecot
"Aug 02 00:13:04 master: Info: Dovecot v2.2.10 starting up 
  for imap, pop3, lmtp, sieve, sieve (core dumps disabled",
which seems to imply that lmtp is enabled.

Any suggestions or advice gratefully received.
  
-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin 2, Ireland