Guru Nanak spent much of his adult life travelling, and the accounts of those journeys have him debating with ascetics, questioning ritual and refusing to identify himself with either of the religious establishments he was born among. Around 1522 he settled at Kartarpur on the Ravi, took up farming, and spent his last seventeen years there with a community that gathered around him.
That settlement is where Sikh practice took its shape. The three obligations later stated as work, remembrance and sharing were not a slogan but a daily routine: the community farmed, gathered morning and evening to sing the compositions the guru was writing, and ate together in a single line without regard to caste, which in sixteenth century Punjab was the most socially disruptive thing about the whole arrangement. Congregation and common kitchen begin here.
So does the succession. Nanak tested his followers and appointed Lehna, whom he renamed Angad, as his successor in preference to his own sons, and had himself bow to him. Authority in the Sikh tradition therefore passed by demonstrated fitness rather than by birth, and the ten gurus are understood as one light in successive bodies.
He died in 1539. The story told of his death is that his Hindu and Muslim followers argued over cremation and burial, agreed to lay flowers on either side of the body and let the fresher garland decide, and found the body gone and both sets of flowers fresh. A shrine and a grave were built, and the river later took them.