Before we begin to study the stanzas, let's recall some brief tenets of Romanticism and Wordsworth's affection for the movement.
Romantic (capital "R") poets were determined to free poetry from the strictures of the past in both subject and style. Rather than the subjects of history and the narrowness of form, Romantic poets turned the focus inward and put the "self" and the individual's experience in the natural world foremost.
So, let's begin with the first stanza:
The speaker is speaking to himself, urging him away from the second hand knowledge of the past that found in books and all of the problems contained therein to which he has no control and no influence.
The second stanza finds the poet alive in the natural world, immersed in life as it happens.
The third finds him freed of the prison of books, relaxing into the music and beauty of nature.
"Let nature be your teacher", the fourth stanza, is the theme of the poem and carries on in more minute instruction of how to be taught until the last stanza.
The final lines are a reproach, to both the reader and the speaker, to remember the lessons learned in the natural world.