Proto-Indo-European is a reconstruction, not a record. No text exists in it and none ever did, and every form assigned to it is inferred from systematic correspondences among the attested languages: Sanskrit, Avestan, Greek, Latin, Hittite, Celtic, Germanic, Slavic, Baltic, Armenian, Albanian and Tocharian. J. P. Mallory and D. Q. Adams's introduction sets out both the method and its limits, and the convention of marking reconstructed forms with an asterisk is a standing reminder that they are hypotheses rather than quotations.
The religious payoff is real but has to be handled carefully. A word for a sky father is reconstructible and lies behind Sanskrit Dyaus Pitar, Greek Zeus Pater, Latin Jupiter and, more distantly, Germanic Tiwaz, which is about as strong as comparative evidence gets. Words for a god, for offering and for sacred formulas can also be reconstructed, and Donald Ringe's work traces the sound changes that connect them across the branches.
What cannot be reconstructed is a mythology. Comparative attempts to recover an Indo-European pantheon and a set of common myths have produced some suggestive parallels and a great deal of overreach, and the atlas records the linguistic correspondences as solid and the narrative reconstructions as contested.