Short answers, pulled from the story.
Mount Meru stands at the center of the terrestrial universe and rises 80,000 yojanas above sea level while extending another 80,000 yojanas below into layers of golden earth and water. The sun and moon revolve around this peak and four continents float in an ocean surrounding its base.
Existence divides into three realms containing thirty-one distinct planes based on mental states rather than physical location alone. These planes include fifteen in the Kāmadhātu realm, eighteen in the Rūpadhātu realm, and four in the Formless Realm Arūpyadhātu.
Human longevity declines from tens of thousands down to under one hundred years during antarakalpa periods alongside rising crimes and hatred. This cycle culminates in a devastating war killing most hostile aggressive people before survivors restore morality and increase lifespan back to eighty thousand years during the reign of Shankha cakravartin king Ajita reborn Maitreya Buddha prophesied future enlightenment.
Sukhavati Western Eternal Land exists as Amitabha Buddha blissful environment accessible through faith devotion merit cultivation located one trillion buddhalands westward direction from Sahālokadhātu current reality. Eastern Abhirati Akshobhya Buddha characterized meditative stability wisdom Vairocana's Lotus Treasury World Padmagarbha-lokadhatu luminous cosmos infinite Buddhas bodhisattvas dwell interdependent billions universes Shingon school symbolizes concept Vajradhatu Garbhadhatu mandalas depicting cosmic body web interconnected beings worlds emphasizing immanence Buddhahood ordinary experience Medicine Buddha Bhaişajyaguru ruling Vaiđūryanirbhāsa Radiant Lapis Lazuli land eastern direction equal grains sand ten Ganges rivers.
Dighanikaya Agganna Sutta sections detail the evolution of humanity and Brahma world origins while Cakkavatti-sihanada-sutta chronicles dynasty lifespans decline rise cycles. Mahapadanasutta records three Buddhas Kakusandha Konagamana Kassapa lived lifespan forty thirty twenty thousand years respectively with current time taken toward end first antarakalpa less than one hundred year life span after Sakymuni eighty-year lifetime ends prophecy future Maitreya reign Shankha king eight zero thousand years duration marks completion cycle ending death births cease entire universe consumed fire water wind destructions sparing highest worlds radiance pleasant fruit levels respectively every eighth sixty-fourth cycles repeating infinitely.