Visual C# Testing...

Hello. I am creating a graphical user interface in visual c# and I am trying to test my GUI without having to publish it. When I use the Ctrl + F5 shortcut, it says that the program builds successfully but the GUI does not appear so that I can test it. How can I change it to where I can test the GUI when the shortcut is pressed? (It does the same thing when I click on the 'Start without debugging' menu toolstrip as well).