Cultivation of Immortality and Seeking the Way

It is said that one can become an immortal by enlightening the Tao, and if one becomes an immortal, one can gain eternity and be free and at ease. Lu Yuan, a young man from a mountain village, occasionally gets the opportunity to embark on the path of cultivating immortality and finding the Tao, but he doesn't know whether he should cultivate first and then realize, or whether he should enlighten first and then cultivate? Lu Zu said in "Knocking Yao Song": Only cultivating one's nature without cultivating one's life is the first disease of spiritual practice; if one only cultivates one's ancestral nature without cultivating elixirs, it will be difficult for the ghost spirit to become a saint for thousands of eons. Sex and fate, which one is more important? Which comes first and which comes last?