I Have a Base in My Mind

The end of the world has come, and all life has been devastated. People have fallen from the top of the food chain to the bottom of the existence, always facing the threat of death. Zombies and mutant beasts have become the new overlords Yang Hao, who has ten years of experience in surviving the apocalypse, returned to before the apocalypse broke out at the moment of his death. What changes will he bring to the doomed end times?