About Sql Server(Posted in .NET coz it's easy)

I want to set a login for a database that i will create in an SQL server instance.
For ex.

After installing Sql Server Express, i will first create a script to create a login.
Then by using the username and password(for the login I created) i will create a database by using script.

Now i want that the database should be accessable by anyone connecting with that username and password only.

Other users, including Windows Authentication and other users should not be able to even see the database.

Please help me.

Sorry, it's not very clear what you want.
When you install SQL Server it's happened either by Windows Authentication mode or using Username/Password and domain name.
Now you wrote:
Actually while you use the second method, without username/password no one will access the Database.

Do you need the installation guide or something like that?

What's unclear ?

I want the database to be opened only by one login, not even by windows authentication.

Ordinarily you can access all the databases when u use windows authentication.