MIGXdb Formtab options & MIGXdb Settings

I am just learning the MIGXdb and need some help understanding the options in the Formtab fields and the MIGXdb Settings.

I can get the 'Input TV' and 'TV Input Type' to work - but I am not sure what is needed in the 'Validation', 'Configs' and 'Restrictive Conditions' fields.

Also, I have a 'Hook Snippet' in the MIGXdb Settings - but can't see how to send a message back to the user if the snippet fails. Is that even possible?

Thanks