Dreamhost doesn't use the public_html model. Instead your domain exists at /home/USER/DOMAINNAME/ Where USER and DOMAAINNAME are substituted for your info.
FWIW, I cite the documentation being poor, rather than dreamhost's methods being bad. While the public_html is a popular place to put web content, its by far not the only way. The documentation making the assumption that public_html exists is what is faulty.