To export and extract information from Google Vault, a list of accounts will need to be provided for Google Vault Extractor to read. This list is a simple text file, where each account is added to a new line with no delineating characters. For more information, refer to the linked Knowledge Base articles at the bottom of this article.
The name of this file will be listed in the Google Vault Extractor command as the "inputFile". For more information on this, read here: KB004975
To determine what data to extract, find out which labels are necessary and which are not. Typically, labels like "Draft", "Spam", and "All Mail" are excluded from a Google Vault migration. Once you have this list, build a search query that returns the expected results and include it in the Google Vault Extractor command. More on that, here: KB004975