1. Login as a Manager, 

Manage - Auto-Mails


Open Mail Settings tab. Where you can see red rectangles please fill this with you gmail account data.

User Name - it's your e-mail address, (f.e testhostel@gmail.com)

Password - password which you are using to login to your gmail account

Display name - Your hostel name

From e-mail - it's your e-mail address,

After all you have to save it, and chceck by Test Email if this settings are correct.

Please let me know if this soluton helped you.