Being Reborn and Forced to Come to a Different World, How Should I Live?

The phantom reset the world again, but the young man looked at it without any resistance. Losing his memory and lying in bed, a traveler in time? Seems to have found him. I went back to my elementary school days and met the girl I remembered. But she doesn't seem to be her? She's back too? The inexplicable pushing hand left him at a loss. Met new friends and time was changed? Forced to come to another world, how to survive alone!