Accessing Gmail Accounts through Mail

Today when I was trying to add my nyu account to mail it always showed the same error message: server rejected your username and password.
 Some people mentioned cleaning the Captcha but it didn't work for my case. So I explored google support and I got the way to figure it out.

First go to account:

Then click on security:

And turn the 2-step verification on (It might require you to login again). After turning it on you will be able Generate new application-specific password by edit Authorizing application and sites.

Each application will need a new password but you will need to enter it once then it's all set.

I still have a lot problems switching from my pc to mac, such as shortcut keys issue and personal settings. And now I should say Mac is a good system, much better than windows in a lot of aspects.