Are you asking for help understanding a specific poem or for guidance in explaining poems in general? If you need help with one particular poem, you need to post again with the name of the poem and the poet.
In general, poetry can be interpreted much as prose is, although poetry may make more use of special writing techniques that sometimes confuse readers. Poems are written about subjects or main ideas, just like novels. A poem may use symbolism to represent some of the things or ideas being portrayed. Poets may choose the words in the poem to convey feelings or emotions or sounds through alliteration, onomatopoeia, or the use of rhyme and meter to create a certain sound when the poem is read aloud. Spacing and placement of lines on a page may also be done to contribute to the overall effect of a poem.