In that leave all fields blank and in “search” field select “Unread mail ” and then click “search mail”.You will be presented with all of your unread emails.For any clarifications / queries , comment here or go to forum
Gmail
Gmail Integrates Task List, Keeps You Organized
The new feature can associate emails with tasks and create multiple to-do lists.To activate Gmail Tasks, you will have to go to Settings/Labs in your Gmail account and right at the top you will find the Tasks module.