How do I implement a file download in Asp.NET MVC 5

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C#

I am doing a an online movie store using Asp.NET MVC 5, whereby customers visiting the site will register and log in before downloading a movie. Now I want to implement a button it in such a way that, when clicked, the customer will start by choosing the destination where to save that movie after that the customer must be redirected to a page that will show the progress bar while the movie is moved from the server to the customer's storage media.