Can't edit duration of audio or photos

Hi, I need your help!

I've imported an audio clip and an image. I'm trying to make a video that's the duration of the audio clip with the image comprising the only visual that lasts throughout.

I select the clips, hit the "Adjust" button, then hit the "information" button and then I believe I'm supposed to see a duration box in the bottom right corner which I can then edit. But there is no duration box! Where is it????

Any ideas?

Thank you!