To answer your thread title, "what the Bible says".
In Revelation 6:9, the Apostle/Prophet John revealed to us that they are under the altar. In Hebrews 12:22-23, Paul or Apollos says that they are in Mount Zion.
In 2 Corinthians 12:4, Paul mentions Paradise as the "3rd" Heaven.
Paul also states that to "be absent from the body is to be present with the Lord".
The Book of Enoch, the first prophet, which is mentioned by Jude in verse 14 and Genesis 5:22, stated that God showed him that Paradise is the 3rd Heaven of 10 Heavens.
Joshua 10:13 mentions the Book of Jasher. So there are other books that have been shunned by for generations that were supposed to be a part of the Bible.
Daniel mentions in chapter 12:4 that in the last days "knowledge will increase". So I believe that these books of Enoch and Jasher will come to light in the next decade or so and enlighten the Church to more that we've been missing for a while now.
Jesus told the thief on the cross that he would be with Him in Paradise "that" day. So that was Abraham's Bosom. But where is Abraham's Bosom?
According to Paul and John and Enoch...etc: The 3rd Heaven.
Now was it in hell before the Resurrection? Of course, because Jesus prophecied that he would be in the belly of the earth for 3 days and nights. So the "today" He told the thief was in the belly of the earth.
But since He rose many from the graves when He resurrected...and there being 24 elders in Heaven right now...it is safe to believe that He took them with Him when He went to the "3rd Heaven".