Visual Studio C#: How to check a value against Access table?

 private void btnConnect_Click(object sender, EventArgs e)
        {
            //I have an Access file, file path: C:\Users\QR\Documents\UserDatabase.accdb ; file password is: Pa$$word123;
            //The access file has a table called User, and the table has a field called UserID (Employee UserID is unique, it is work PC, employee userID is same as Environment.UserName)
            //If Environment.UserName is not in the table, then it is first time that the person uses this application, and it will loop to another Registration form.

        }

I will need to write code to check if Environment.UserName is not in the table , how do write it? In general, I have no idea how to connect Visual Studio to Access database.

Thanks.