Hello, it's occurred to me that I don't know the difference between sheol, hades and hell.
Well, in the OT, there are only two terms used for the terms you mentioned.
Sheol - which is hebrew, and it simply means the grave. It's where the dead rest. No consciousness, just rest, until the resurrection, or someone speaks to the dead and awakens them temporarily (which is never a good idea).
The second:
Tartarus - Which, again is hebrew, and it's a holding place for angels that have sinned against God or man. Either for having sex with women, or for leading men astray, or for blaspheming, basically any sin at all.
These are the only two terms ever used in the OT to describe the terms that we call hades and hell.
"Hell" - has been used to replace one or both of the two terms I described above, but after much study into the subject, I've found that Hell, comes from the nordic "goddess" "Hel". She was the daughter of "Loki" and was the ruler of the underworld. She was responsible for tormenting and torturing souls that went there. Although, no where in the bible is there mention of an eternal soul. We are to live forever with Jesus, but we're supposed to sleep in death, until the resurrection. At that time, we'll be given new bodies that are incorruptible, with which we'll reign with Jesus here on earth. There's not really ever a talk about an eternal soul being punished in "hell". That's a pagan philosophy that dates back bast the time of the egyptians.
"Hades" - is the same exact thing as "Hel". He's the ruler of the underworld, but instead of Nordic paganism, Hades belongs to the Greek's.
This begs the question, where do we go if not eternally to "Hell"?
Well, what happens to someone who comes into the presence of God, without a savior? God is an all consuming fire - so they simply burn up, as Nadab and Abihu did, so will those resurrected unto judgement without the testimony of Jesus and a walk purified by Him (the word). We won't be punished for all eternity by being tortured by demons. The demons are spirits of the fallen ones, that are also marked for judgement, so how would they be punished, if they get to reign and do what they love to do for all eternity? They too will be punished. What happens to us when we die, and are resurrected to judgement, is we simply burn up in the presence of the Almighty God, and cease to exist. There is no soul, and there is no eternal punishment. It talks about a lake of fire, but I think that's more so talking about because of how many people will be resurrected to judgement that will be devoured in the consuming fire of our Creator, the road is wide.
Heaven, comes from the hebraic word Shamayim, which just means sky. There's different levels of the sky and the bible talks about this, but it's not where we go when we die if we've been accepted and saved. We are resurrected, and as I wrote above, we will be given a new resurrected body for life here on earth to reign with Him in New Jerusalem. There will still be people here on earth during that time that we will live amongst. We will reign and rule over them, with Jesus as our King, in Israel. (Not the country Israel of today, but the Israel that God Himself will set in place, and in doing so, He will bring all 12 tribes of Israel back to live in Israel. Of which, we - Gentiles - are grafted in as Romans 11 talks about, through the tribe of Ephraim. And actually Genesis 49 talks about this too. On several times, though it's translated as completeness of the nations, in the hebrew it literally means fulness of the gentiles.)