Go to the Review My Poetry board if you want a critique. If you just want readers, go to the Gallery.
Start a New Topic, just as you did here.
Copy your poem from where it is written and paste it into the new topic.
Post.
If your poem is specially formatted, you will have to work to put the formatting back prior to posting. You might want to hit Preview before you hit Post so you can correct the look - if the look is important.