If you are a beginner, I would start with the basic template. The advanced template includes multiple environments, separate front and backend sites (as well as common folder) and database user system, which are useful but will be confusing for a beginner. You can always add the extra stuff manually afterwards when you are more comfortable with using Yii.
For admin panel, it depends what you are doing but if you are a beginner, it is a lot of work to learn a framework and then build a site that is like wordpress. You can use Yii’s built-in tool called Gii and it will generate basic editing pages (we call it CRUD for Create Retrieve Update Delete) but these will only provide very simple functionality. You will also need to consider the security functions to hide the admin functionality for other users.
Good luck though, go and find some tutorials on YouTube if you want to give yourself an introduction.