User Login With Database Verification

I have a table ‘user’ with following fields id, email, username, password, firstname, lastname, and country.

now i want to add user login with this table in default site login. Check username or email, and password from database for login.

This should get you started:

I can’t completely understand this tutorial.

Which part is giving you trouble?

You should probably start with the guide if you’re completely new to Yii.