As best I can describe it, man has flesh, man has spirit, and where the two interlap forms the soul.
To understand what happens at death one must understand the relationship of time and eternity. There is no "Time Line". Rather, consider it to be like a wheel - with God/eternity in the hub and time running along the rim. God's interaction with time is like lacing a wheel. Run a spoke from the hub to the rim at the 12 o'clock position. Then another at 8. Then another at 4. And so on. This way we can see how God is able to interact with all of time, at all of the time.
Today you'll be with me in paradise - but your body will lay waiting for resurrection. How does that work? When you die, your spirit is immediately caught up to be with God, at the point of Christ's return. That your-ticket-is-punched moment is your rapture. As such, even tho our bodies die at different times, our spirits all arrive before Jesus at the same time. Which in His realm is as He returns.
On earth, on the rim, our bodies lay rotting in time for resurrection. Finally, on the rim's last day, Jesus resurrects them to be with Him when He returns.
Now, if our spirits arrive when He returns, and our bodies arrive when He returns, then even tho our bodies rot for years on the rim, in the hub we were never without it. Thus while on the rim, there was no interlapping of flesh and spirit to form a soul, and in that sense the soul slept; in heaven our souls never ceased as our spirits and flesh arrive at same time.