As when any mortal dies, Jesus's spirit separated from his body immediately upon his death. While his corpse was laid in a tomb for three days, Jesus went to the Spirit World. In the part of the Spirit World known as Paradise, Jesus preached his gospel to the righteous.
He then appointed missionaries to go to the other part of the Spirit World known as Hell and preach the gospel to the wicked who have the fiery indignation and wrath of God upon them. Jesus preached in both Paradise and in Hell. He was the first man who ever went to preach to the spirits in Hell.
On the third day after his death, Jesus became the first person to become resurrected, which is to say his spirit reentered his body and cannot be separated from it again. All the righteous people who lived and died before Christ also came out of their graves and were resurrected as well. Many in Jerusalem witnessed them. They were then crowned in heaven at the right hand of God.
Over the next 40 days, the resurrected Jesus ministered to his apostles, instructing them to bring the gospel to all nations. It was during this time that the apostle John asked Jesus for the power to remain on earth preaching the gospel until The Second Coming, and Jesus granted him this power. The apostle John went on to write the Gospel of John and the book of Revelation, and he is still alive to this day.
At the end of this period with his apostles, Jesus ascended bodily into heaven. Note that Jesus did not have a fulness until he was made perfect through his suffering and received his resurrected body. Although he had been a God before, there were some things he lacked until after his resurrection. In his current exalted state, Jesus has a fulness of the godhead within him.