1. You have to create a user with uid 202: dovecot
2. And a group with gid 202: dovecot
3. You have to create a user with uid 248: dovenull
4. And a group with gid 248: dovenull
5. Configure dovecot config file: /etc/dovecot/dovecot.conf
   There is already an example file included in /etc/dovecot/
6. Copy directory /usr/doc/dovecot-2.1.10/example-config/conf.d/ to /etc/dovecot/ (cp -R /usr/doc/dovecot-2.1.10/example-config/conf.d/  /etc/dovecot/)
7. Cd to /usr/doc/dovecot-2.1.10/ 
   Edit dovecot-openssl.cnf and set variables. Then run "sh mkcert.sh"
8. Edit files 10-auth.con, 10-mail.conf, 10-ssl.conf, auth-system.conf.ext  in /etc/dovecot/conf.d/ directory and set variables.

NOTE: Step 1-2 can easily be done by 'sh config-helper.sh' in current
directory.
Step 3-4 can easily be done by 'sh config-helper-dovenull.sh' in current
directory.

Have fun :-)