First off, why are you using VS 2013 when VS 2017 is available? Get VS 2017 and .NET Core.
https://www.visualstudio.com/downloads/
Second, what? What are you trying to do here? You can't connect to a server you're not the root user for. If you're attempting to connect to anyone's server but your own, you're going to have a bad time. A connection string is provided by the business hosting your server. For example, Microsoft Azure provides each of their cloud server subscribers with connection strings to connect to that server. In web.config, if I recall correctly, you simply scroll to the top of the page and paste the connection string into the connection string element. Then enter your password and name into the string where the password and name placeholders are.