Adding a silent section

[efiste2]

Im creating a DVD and adding a sound effect to the menu ( a train whistle 2 seconds long) , However he software simply loops the audio track so the whistle sound just carrys on and on, which is very annoying.
My idea is to add a long silent section after the whistle, so that the DVD menu simply plays one whistle but carrys on playing the added silent section. How can I add a silent section using AUDACITY ?

[hello_hello]

How can I add a silent section using AUDACITY ?

Via the Generate/Silence menu.