This is a wonderful question, and I am happy to help you explore the subject as it is treated in The Urantia Book. It is actually a more elusive subject than one might think at first glance. In this following quote we find the first mention of the will of God:
This quote explains that the will of God is present in our world, but it exists only in the Spirit of God which indwells all normal-minded mortals. The good Spirit actually IS God, and is our only means of contacting God outside of Paradise. This is a wonderful and reassuring truth—that God actually DOES indwell our minds, and through our own efforts, we can use this indwelling presence to progressively discern the will of God.
(1:3.6) In the universes God the Father is, in potential, the overcontroller of matter, mind, and spirit. Only by means of his far-flung personality circuit does God deal directly with the personalities of his vast creation of will creatures, but he is contactable (outside of Paradise) only in the presences of his fragmented entities, the will of God abroad in the universes. This Paradise spirit that indwells the minds of the mortals of time and there fosters the evolution of the immortal soul of the surviving creature is of the nature and divinity of the Universal Father. But the minds of such evolutionary creatures originate in the local universes and must gain divine perfection by achieving those experiential transformations of spiritual attainment which are the inevitable result of a creature's choosing to do the will of the Father in heaven.
This following quote further explains just how we, as mortals of earthly origin, grow to adopt the leadings of the indwelling Spirit, the "will of God, " thereby achieving ultimate eternal survival. When we choose to be led by the Spirit-within, we then create that indestructible entity known as the soul, which is the very part of us that survives.
Although you did not specifically ask, I thought you might like to have further information regarding the will of God—for example, how the will of God is discerned and performed in a human life. How do we actually DO the will of God? These quotes may give you some direction and encouragement:
(1:3.7) In the inner experience of man, mind is joined to matter. Such material-linked minds cannot survive mortal death. The technique of survival is embraced in those adjustments of the human will and those transformations in the mortal mind whereby such a God-conscious intellect gradually becomes spirit taught and eventually spirit led. This evolution of the human mind from matter association to spirit union results in the transmutation of the potentially spirit phases of the mortal mind into the morontia realities of the immortal soul. Mortal mind subservient to matter is destined to become increasingly material and consequently to suffer eventual personality extinction; mind yielded to spirit is destined to become increasingly spiritual and ultimately to achieve oneness with the surviving and guiding divine spirit and in this way to attain survival and eternity of personality existence.
So, we can now see that the "will of God" is truly an "inside job." The will of God exists in the form of the indwelling Spirit of God in the minds of mortals (known in Urantia Book teachings as the Thought Adjuster, or Mystery Monitor), and the finding and doing of that will consists in sharing that inner life—the life apart from the purely mechanical function of the brain—the life of the mind, and in the arena of free will. In other words, it is our mandate to choose, of our own free will, to do the will of God, allowing the leadings of the indwelling Spirit to inform our choices in life. Finally, I chose the following quotes to give you an even broader view of the function of the will of God in the mind of man.
(111:5.1) The doing of the will of God is nothing more or less than an exhibition of creature willingness to share the inner life with God—with the very God who has made such a creature life of inner meaning-value possible. Sharing is Godlike— divine. God shares all with the Eternal Son and the Infinite Spirit, while they, in turn, share all things with the divine Sons and spirit Daughters of the universes.
The imitation of God is the key to perfection; the doing of his will is the secret of survival and of perfection in survival.
(111:5.6) This choosing of the Father's will is the spiritual finding of the spirit Father by mortal man, even though an age must pass before the creature son may actually stand in the factual presence of God on Paradise. This choosing does not so much consist in the negation of creature will —"Not my will but yours be done"—as it consists in the creature's positive affirmation: "It is my will that your will be done."
(12:7.7) The will of God does not uniformly prevail in the heart of the God-seeking material mortal, but if the time frame is enlarged beyond the moment to embrace the whole of the first life, then does God's will become increasingly discernible in the spirit fruits which are borne in the lives of the spirit-led children of God.
(34:7.6) ... present-day mortals would experience less of this apparent warfare between the flesh and the spirit if they would enter the spirit kingdom, wherein the faith sons of God enjoy comparative deliverance from the slave-bondage of the flesh in the enlightened and liberating service of wholehearted devotion to doing the will of the Father in heaven.
(39:4.14) The keys of the kingdom of heaven are: sincerity, more sincerity, and more sincerity. All men have these keys. Men use them—advance in spirit status— by decisions, by more decisions, and by more decisions. The highest moral choice is the choice of the highest possible value, and always—in any sphere, in all of them—this is to choose to do the will of God. If man thus chooses, he is great, though he be the humblest citizen of Jerusem or even the least of mortals on Urantia.
(107:0.4) Any mortal who has seen a Creator Son has seen the Universal Father, and he who is indwelt by a divine Adjuster is indwelt by the Paradise Father. Every mortal who is consciously or unconsciously following the leading of his indwelling Adjuster is living in accordance with the will of God. Consciousness of Adjuster presence is consciousness of God's presence.
Thanks so much for your question. It is an important one, and I hope my reply has been helpful