The Jehovah's Witnesses don't believe in the soul as a spiritual, essential self inhabiting the body. They rightly read the Bible (at least the Old Testament) as lacking such a concept. They recognize the "ghostly soul" idea as heathen (specifically Hellenist).
So what about the afterlife? The JWs correctly see in the Bible no "afterlife," a heathen, European concept. Instead, they see the Bible promising a resurrection of the body here on earth. Everybody (except for those who have committed the unforgivable sin of apostasy) gets raised from the dead to live in justice and peace for a thousand years, during which time they can prove themselves worthy of eternal life. (That's Judgment "Day," as a thousand years is but a day to Jehovah.)
The body that appears for the Last Judgment is a new creation, an exact duplicate of the original body. Presumably Jehovah has the good sense to copy the way the body was at some point after it matured and before it got too old or damaged. I wouldn't mind me at age 17 (but as an apostate I don't get in, so the point is moot). Apparently, though, you get the brain you had at the end of your life, so you can remember what happened when you were alive.
The whole resurrection business is a little tricky because there's no soul. There is no "same soul" of the deceased to get put into the new body. The new body is all there is. But what good is it if you die and a duplicate of you gets created to enjoy the new heaven and the new earth? The JWs aver that it's really you, but they're hard-pressed to explain in what sense a duplicate, even a perfect duplicate, is "really you." If Jehovah made a duplicate of you right now in another time zone, you wouldn't experience what that clone experiences. So why would you experience what a clone in the future experiences?
It's nice to know that everyone will be resurrected for the Last Judgment (at least you non-apostates). Too bad, though, that it's the clones who'll be inheriting paradise.
PS: While we can all understand why Jehovah wouldn't want apostates kicking around His new earth, here's a trick He apparently hasn't thought of. Why doesn't He duplicate apostates for the Last Judgment, like everyone else, but just copy their bodies and brains from a time before they committed apostasy? (For me, that would be like age 8.) Since there's no soul to be tarnished by the sin of apostasy, the duplicate of the not-yet-apostate would have committed only forgivable sins.
"Not so fast, there, buddy!'