I use a chromebook... however I don't record or upload or use it for librivox except for visiting the website and putting in claims etc. So I've looked into it:
You can't use your chromebook for audacity specifically. It won't download it. You cannot download a lot of other "apps", unless they are through the play store. Everything you can download is in the play store. That's what I've learned. There are a couple of recording apps and things there, but there's no real editing type of app there unfortunately.

I wish I could help you out and show you something that works, but unfortunately that's not the case. The most I can recommend, or ask, is if you have a windows or mac.
Hope you find something that works, and if you need some advice for that we're here too.

<smile>