Enabling code coverage for seperate project in visual studio

I am trying to start unit testing an existing C# application using the default unit testing library. I have created a new "Tests" project where all the tests are to be kept and I have some basic tests working but the code coverage report is not working.

At the moment it assumes I'm looking for code coverage of the Test project and not the main project itself. Where can I change it so that it is analysing the Main project and not the Test project for Code Coverage?