如何在新建故事板后手动添加根视图控制器箭头?

I was just created a new storyboard for test, rather than bother the main storyboard. so when if I was testing, I would like to use the new storyboard I can managed add some view controllers, and I can start the storyboard as well as one of the controller in source code, but how to make a view controller in the storyboard, as there isn't the arrow as the main one!I was just created a new storyboard for test, r