what are these for i am really not understanding when click add account names are present with check box what are these for how can be they be used :)

Read about Accounts and Privileges in your User Manual.

i know about the both i want to know how to use them what is the use of ext privileges

Link

answer rejected i want in words

Here are words: http://help.filemaker.com/app/answers/detail/a_id/5838/~/a-compendium-of-filemaker's-security-features-with-useful-notes-and-information

PS: Apparently, English is not your native language, and so your rude response to Lee will be excused, this time. If you want help on these forums, you'll need to read the documentation and ask a much more specific question. We understand when a new user doesn't know the terminology. We'll guide you then. Obviously, you know it's called Extended Privileges. Read about them, and then ask your question.