how to set role access for specific folders in asp.net

I have an Asp.net project,
i want admin users access admin folder and other members just can access member folder (pages) , and not to access admin folder.

This is my Web.config Code

So my question is , how i create and define a user as admin?

in sql server i defined roles for users, but how can assign that users role in my webconfig

i mean, webconfig dont recognize my sql roles.

ps. i tried to add roles from asp.net configuration , but didnt find any asp.net configuration in my menu

thanks.