As I see it, the 'spirit' (gestaltic sphere of 'nuclear points') exists in the spiritual plane (highest vibration). Think of it as a 'celestial sphere’ that can be micro- or macro- sized almost simultaneously and of a heavenly hue and resonance. It is everything God Good that you've become over the 'eons'. It is your 'spiritual essence' and is distinctively and infinitely unique.
Your God Spirit projects Light and Love through a 'tube of light' into the physical plane (denser realm) where 'you' are 'manifested' aka 'incarnated' as a soul containing ‘characteristics’ that you have as strengths and weaknesses in working through your personal karma.
Prior to birth, your spirit guides help you to choose a life situation for you to incarnate into that will provide you with the opportunities and challenges that you need to best continue your evolution as a spiritual being. At the end of life, when your spirit disconnects itself from your physical body, you lose consciousness and the physical body begins to die (the reverse of the birthing process). The person’s essence is drawn back into the soul body and any truly purified elements are drawn into the spirit body.
Believing or not believing whether or not you have a soul is a matter of free will. Properly interpreting the details about life experiences along The Way by your Angels will help. Believing or not believing in Angels depends on meaningful life experiences.
Conclusion: Live a full and meaningful life and be genuinely aware of life’s subtleties so that they may show you The Way.