Requirement: create the LDIF file and importing the creted LDIF file in to the TDS server?

Entire concept is new to me......ITDS version 6.3 was already installed.

1) what is LDIF file?
2) why and where we have to create and LDIF file and how it is possible?
3) How and why we have to import LDIF file in to ITDS server?
4) what is LDAP server?
5) what is the relation between ITDS server, LDAP server and LDIF file?
6) Is ITDS server enough to meet above mentioned requirement?

Can u guzzzzzzz....plzzz help me out of this?

Thanks in advance....:-)