These are the documents referenced in The Blueprint for Two Americas.
Written in 1933 primarily by Raymond Bragg and published with 34 signers. This manifesto talks of a new religion and refers to humanism as "the religion of the future."
Written in 1973 by humanists Paul Kurtz and Edwin H. Wilson, Humanist Manifesto II is an update to the previous Humanist Manifesto, and the second entry in the Humanist Manifesto series.
Humanism and Its Aspirations subtitled Humanist Manifesto III, a successor to the Humanist Manifesto of 1933 is the most recent of the Humanist Manifestos published in 2003.
This 2020 document for the Biden/Harris campaign provides recommendations that will reverse many of the accomplishments of the Trump administration and is a blueprint to restore a vision of constitutional secularism for religious and intellectual pluralism.
Additional supporting documents the message written in The Blueprint for 2 Americas.