1.

apt-get update
apt-get install debian-archive-keyring openssl-devel libwww-perl make gcc g++ make libxml2-dev

libperl-dev libperl5.10 nano perl-base perl-modules
apt-get update
apt-get upgrade
apt-get distr-upgrade

If you wish you can skip this part where I tell you to install certain packages and ask stupid questions in comments.

2.

wget http://www.directadmin.com/setup.sh

3.

chmod 755 setup.sh

4.

run ifconfig and note down your interface and ip number
run hostname and note down your hostname

5.

./setup.sh

You will be prompted for a client ID number, license ID number, and hostname.
Enter those details and hit enter. Wait. Yeah… it takes some time
Note down your password

6. Install spamassassin

cd /usr/local/directadmin/scripts
./spam.sh

7. Are you ready for manual configuration? [yes] no

8.

/usr/bin/spamd -d -c -m 15

9.

nano /etc/exim.conf

and check to have those lines uncommented

# Spam Assassin
spamcheck_director:
driver = accept
condition = “${if and {
{!def:h_X-Spam-Flag:}
{!eq {$received_protocol}{spam-scanned}}
{!eq {$received_protocol}{local}}
{exists{/home/${lookup{$domain}lsearch{/etc/virtual/domainowners}{$value}}/.spamassassin/user_prefs}}


{<{$message_size}{100k}}
} {1}{0}}”
retry_use_local_part
transport = spamcheck
no_verify

10.

/etc/init.d/exim restart

11. http://server.ip.address:2222

You can edit /usr/local/directadmin/conf/directadmin.conf and change directadmin port