I'm not completely clear, but it seems to say that Qui-Gon died and went to the Nether World of the Force, but was helped back by a Whill shaman, and after that, he helped other Jedi, as they died, avoid the trip to the Netherworld of the Force. This implies that when Qui-Gon died and went to the Netherworld, he maintained enough of his own individuality and self awareness to find his way back, apparently either intact or mostly intact.
But Force ghosts eventually have to go to the Netherworld of the Force, because all things die (but apparently one Whill Shaman found a way to be immortal).
This leads to two related questions:
1) Why do Force ghosts have to leave for the Netherworld of the Force?
2) What happens when one goes to the Netherworld?
If Qui-Gon has been there and it's known that Yoda met two people there, then there must still be some sense of individuality in the Netherworld. Is it the Force equivalent of the Summerlands or heaven or something like that?