How to add dynamic dropdownlist with sql database in mvc 4

Question

Hi,

 I am developing an MVC 4 application now i need a tutorials that explain clearly about  create a dynamic dropdownlist with sql database usage. Please provide me guys.

1. I going to have a three dropdownlist in a view page.

2. I need connection string that help me to connect with sql db.

3. where i should place sql queries(controller or model) and how to make communication with those thing.
please guys i am beginner.

Thank you.