A choral ode typically consists of a strophe, antistrophe, and epode, with the strophe and antistrophe having identical metrical patterns. The reason for this patterning had to do with the associated dance movements. In the strophe often the chorus would move in one direction, and then return to that position during the antistrophe by moving in the opposite direction.

When the Romantics appropriated the ode form, they actually imitated the Pindaric form more than the more narrowly constrained dramatic form of choral ode, and often simply use the term "ode" for poems with irregular forms. Nonetheless, the poem does show some traces of this structure, with several paired stanzas, but there isn't really a singular, well defined epode. As is often the case with Wordsworth, there is a thematic progression from some remembered childhood joy to present despair, followed by a rediscovery of joy in children and nature. 

NB: The phrase "a poem should not mean, but be" is not from Eliot, but from "Ars Poetica" by Archibald MacLeish.

First of all, the term "epode" does not comfortably describe any part of Wordsworth's poem -- it is a term from Greek drama and epic describing a certain metric formation that was integral to the shape of the legend being described.  Wordsworth's Romantic poetry takes an altogether different attitude toward its intended audience.  Secondly, since each stanza of the poem takes on the same metric pattern, it is difficult to know to which stanza you refer.  And finally the term "explain" is vague at best.  In discussing a poem's "meaning" we remember Eliot's reprimand: "A poem must not mean, but be."  Perhaps your question could be rephrased for clarity.  This poem has long been analyzed and discussed, but its central point is crystal clear at first read: We seem to have come from another plane of existence, whose memories fade as Mother Earth (our present physical state) fills our laps with new "toys" of experience.