for adding new key-value pair in existing section:
--------------------------------------------------
You have to add key-pair definition into existing validator list like
this example from User1 section. 

("serial_enable_ipmi_msgs"         ;; key string 
 valid-boolean?		           ;; validation procedure 
 get-boolean		           ;; conversion procedure(COMMIT)
 commit-serial-enable-ipmi-msgs    ;; commit procedure
 checkout-serial-enable-ipmi-msgs  ;; checkout procedure
 get-boolean-string		   ;; conversion procedure(CHECKOUT)
 same-string-ci?		   ;; diff procedure
 "Possible values: Yes/No")        ;; doc string

key string::
    a key in the section for checkout/commit/diff

validation procedure(COMMIT)::
    This procedure validates the user given value to the keystring.
    It returns the value is valid or not.  For example, user may enter
    "Yes" / "No" / foobar for "serial_enable_ipmi_msgs"
    key. valid-boolean? procedure checks and returns true if entered
    value is "Yes" / "No"; else returns false

conversion procedure::
   This procedure converts the user given value for commit procedure.
   get-boolean procedure converts "Yes" / "No" to #t / #f for commit
   procedure.

commit procedure:: 
   This procedure is used for committing to bmc for the key.

checkout procedure::
   This procedure is used for checkout from bmc for the key.

conversion procedure(CHECKOUT)::
   This is used to convert bmc value to user readable value.  For
   example get-boolean-string procedure converts #t / #f to "Yes" /
   "No".

diff procedure::
   This is used when user asks for differences between bmc and
   inputted-value.

doc string::
   This is displayed as a help in checkout configuration file.


Section name       Validator list                     Filename
==================================================================================
LAN-Conf-Auth      lan-conf-auth-keys-validator       bc-lan-conf-auth-section.scm
LAN-Conf-Misc      lan-conf-misc-keys-validator       bc-lan-conf-misc-section.scm
LAN-Conf           lan-conf-keys-validator            bc-lan-conf-section.scm
LAN-Channel        lan-serial-channel-keys-validator  bc-lan-serial-channel-section.scm
Serial-Channel     lan-serial-channel-keys-validator  bc-lan-serial-channel-section.scm
Misc               misc-keys-validator                bc-misc-section.scm
Serial-Conf        serial-conf-keys-validator         bc-serial-conf-section.scm
User1              user-keys-validator                bc-user-section.scm
User2              user-keys-validator                bc-user-section.scm
User3              user-keys-validator                bc-user-section.scm
User4              user-keys-validator                bc-user-section.scm

** you can find all validator list at the end of respective file.


For adding new section:
-----------------------
You can do this by adding a dotted-pair in section-name-desc list of
bc-section.scm.  For example

("misc"           . misc-keys-validator)

This means, a section name  and respective validator list


For common procedures:
----------------------
You can get common procedures from bc-common.scm file.