What happens when you die?
Death is not the end of you. The Urantia Book teaches that a real entity, the soul, survives the death of both body and mind. You sleep, and you awaken on a new world where personality is reassembled, with your identity intact and your spiritual guardians in attendance.
In the book's own words
There is something real, something of human evolution, something additional to the Mystery Monitor, which survives death. This newly appearing entity is the soul, and it survives the death of both your physical body and your material mind. This entity is the conjoint child of the combined life and efforts of the human you in liaison with the divine you, the Adjuster. This child of human and divine parentage constitutes the surviving element of terrestrial origin; it is the morontia self, the immortal soul.
The better next question
What are the mansion worlds?