Many web applications are configured to run a website on your machine, IIS localhost.
To make it easier on yourself:
- Open Visual Studio as an administrator. Your instance of Visual Studio should have (Administrator) in the title bar.
- Let Visual Studio create the site in IIS for you automatically.

If you open a solution and notice that the project has failed to load, this is probably because your Visual Studio is not run as administrator. Restart the application and select Run as administrator.