To paraphrase a piece of poetry or writing means to give an explanation of the piece without plagiarizing. The word paraphrase means to "restate the text to give the meaning in another form."
Do not get paraphrase mixed up with plagiarism. Paraphrasing means to use your own words to summarize, so every thought should be as original as possible. Do not quote directly from the poem, or you dip into plagiarism, which is illegal due to infringement on copyright laws. Try to be as far from the poem as possible without straying from your topic so that the reader can still understand the general idea.