From the instructions, which I’ve now amended slightly to (hopefully) make it more clear:
Your poem must be your original work and you must:
- grant us irrevocable, non-exclusive rights to publish your poem with attribution in our publication, and
- grant our readers irrevocable, non-exclusive rights to record their reading of your poem and publish that recording online, with attribution.
That is, if you have granted anyone else the exclusive rights to publish your poem online or to publish recordings of your poem (subsidiary rights), or if you intend to do so, we can’t accept your poem for this project. But if you’ve granted non-exclusive licences and/or retained all rights, we can still accept your poem.
You’re allowed to submit a poem that’s already been published, so long as the licence you’ve granted that publisher allows us to re-publish it.
So if you’ve published it somewhere that requires “exclusive rights” or “exclusive digital rights” or “all rights” or “exclusive subsidiary rights” (which would include the right to record audio), then we can’t use your poem without licence infringement, so we won’t accept it.
If you sign up as a poet, you’re explicitly giving us an irrevocable, non-exclusive licence to publish your work in our online publication and to let other participants read your poem and record it. Because these rights are irrevocable (you can’t take them back) you will never be able to grant someone else an exclusive licence to record your work or publish it online…but you can grant as many non-exclusive licences as you like.
Does that make more sense?