[exim] Configuring Exim4 with MySQL for VirtualDomains

My goal is to set up a mail server to support multiple domains

I do this:
1- Create a mysql database named maildb
2- grant select,insert,update,delete on maildb.* to mail@localhost
3-flush privileges
4-create table users with this (CREATE TABLE users (
    id                    char(128) DEFAULT '' NOT NULL,
    crypt                 char(128) DEFAULT '' NOT NULL,
    clear                 char(128) DEFAULT '' NOT NULL,
    name                  char(128) DEFAULT '' NOT NULL,
    uid                   int(10) unsigned DEFAULT '65534' NOT NULL,
    gid                   int(10) unsigned DEFAULT '65534' NOT NULL,
    home                  char(255) DEFAULT '' NOT NULL,
    maildir               char(255) DEFAULT '' NOT NULL,
    quota                 char(255) DEFAULT '' NOT NULL,
    KEY id (id(128))
);)
5-Create maildir with this mkdir -m 0700 Maildir; mkdir -m 0700 
Maildir/{cur,new,tmp} in this 
folder /usr/local/vdomains/mail/prueba.com/users/prueba/Maildir
6-Create table domains with this (CREATE TABLE domains (
   userid char(128) NOT NULL default '',
   KEY userid (userid)
);)
7-INSERT INTO domains (userid) VALUES ("prueba.com");
8-INSERT INTO users (id, crypt, clear, name, home, maildir) VALUES (
   "prueba@???", encrypt('abcd'), "lrepsak", "prueba",
   "/usr/local/vdomains/mail/prueba.com/users/prueba",
   "/usr/local/vdomains/mail/prueba.com/users/prueba/Maildir");

Here is the problem I need to include this

local_delivery:
driver = appendfile
group = mail
mode = 0660
mode_fail_narrower = false
envelope_to_add = true
return_path_add = true
directory = /home/${local_part}/Maildir/
maildir_format

somewhere in Exim configuration but I don't know where and why

and this too
address_directory:
driver = appendfile
no_from_hack
prefix = ""
suffix = ""
maildir_format