Step by step, easy does it.

Here are some mental mapping for you to consider for the switch from Kohana to yii.

• Aside from themes and assets (images, js, css), and the bootstrap file (index.php that includes and calls the yii framework) everything else should be in the protected folder
• the protected folder must have at least 1 folder, the controllers folder
• the controllers folder contains the controller files, thus aptly named
• controller files are named as: [name]Controller, and contains the class [name]Controller extends CController
• the default controller must have at least one function, public function actionIndex(), which is the default action shown. This is similar to Kohana's Index() function
• the views are placed in the views folder
• views for particular controllers must be placed in a folder with the name of its controller. Example: the views SiteController uses must be placed inside views/site