A standard file (for Linux) looks like:
------------------
#
# To have more informations about Proftpd configuration
# look at : 
http://www.proftpd.org/
#
# This is a basic ProFTPD configuration file (rename it to
# 'proftpd.conf' for actual use.  It establishes a single server
# and a single anonymous login.  It assumes that you have a user/group
# "nobody" and "ftp" for normal operation and anon.
ServerName                      "ProFTPD"
ServerType      inetd
ServerType      inetd
DefaultServer                   on
<Global>
DefaultRoot     ~               psacln
AllowOverwrite          on
ListOptions "-a"
</Global>
DefaultTransferMode     binary
UseFtpUsers                     on
# Port 21 is the standard FTP port.
Port                            21
# Umask 022 is a good standard umask to prevent new dirs and files
# from being group and world writable.
Umask                           022
# To prevent DoS attacks, set the maximum number of child processes
# to 30.  If you need to allow more than 30 concurrent connections
# at once, simply increase this value.  Note that this ONLY works
# in standalone mode, in inetd mode you should use an inetd server
# that allows you to limit maximum number of processes per service
# (such as xinetd)
MaxInstances                    30
#Following part of this config file were generate by PSA automatically
#Any changes in this part will be overwritten by next manipulation
#with Anonymous FTP feature in PSA control panel.
#Include directive should point to place where FTP Virtual Hosts configurations
#preserved
ScoreboardFile /var/run/proftpd/scoreboard
# Primary log file mest be outside of system logrotate province
TransferLog /usr/local/psa/var/log/xferlog
#Change default group for new files and directories in vhosts dir to psacln
<Directory /home/httpd/vhosts>
        GroupOwner      psacln
</Directory>
Include /etc/proftpd.include
-------------------
Proftpd is through xinted. You must restart xinetd:
/etc/init.d/xinetd restart
in order to restart proftpd.