Create only the mail database.
Enable the 'Admin' button for the both Roundcube themes (larry and classic).
Install the mailserver administration GUI and the domain admin app.
Install the system (postfix, dovecot, dkimproxy, clamav, spamassassin, roundcube).
Stop the mailserver administration GUI and the domain admin app.
Reset all mysql databases (mail, spamcontrol, and webmail).
Execute the mailserver administration GUI and the domain admin app.
Send the system mail to the first administrator.
Generate SHA256 file, that contains the config files checksum.
Backup all system config files.
Enable dkim for all domains.
Export mail database, and a specification file for mail folder. The files are app.sql.gz and special.var_mailserver_mail located in the backup folder.
Import mail database, and populate the mail folder.