The 8th time we see the word Sheol in the Old Testament is in 1 Samuel 2:6. Note that neither Joshua, nor Judges (the 6th and 7th books of the Old Testament, respectively) give any mention of the word Sheol.
In this context, a young woman named Hannah is saying a prayer of thanksgiving to YHVH for giving her a son, Samuel, whom she "loaned" to YHVH for all of his life. Her prayer encompasses 1 Samuel 2:1 to 1 Samuel 2:10 and is a good example of a praise to God.
Of interest to us, when looking at Sheol, is the passage at 1 Samuel 2:6 which states:
"YHVH kills and keeps alive. He brings down [to] Sheol and brings up."
When we look at this passage it should be pretty clear what we've discovered already. Sheol is the grave - a place of death, and it is down beneath the earth.