You can then configure various options from the popup.
Options and their Usages
Check for New Mails Every 'n' Seconds - This option determines at what intervals should the app check for new unread emails in your Outlook.com Inbox. The default value is 15 seconds and can be increased upto 1 minute. The various steps includes -
15 seconds
30 seconds
45 seconds
1 minute
Show Desktop Notifications - This option determines if Desktop Notifications like as shown below should be displayed or not upon finding new unread emails.
Show Notifications with Sound - This option determines if Desktop Notifications like as shown above should be displayed or not upon finding new unread emails with a sound. Turning this option OFF will not prevent the Notifications from being shown but doesn't produce a sound.