Gehenna was the garbage dump outside Jerusalem obviously this is what we think of as hell where you burn the refuse. Sheol was were Jesus descended to preach to the prisoners 1 Peter 3:19 or so and relates also to the apostles creed and you can throw Eph 4:8-10 and Psalm 68:18 into that thought and Hades is where you go if you vote democrat. Hell we don’t know and neither does anyone else for sure.