Acts 1:4  And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me.
5  For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
6  When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?
7  And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.
8  But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.
9  And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight.
10  And while they looked stedfastly toward heaven as he went up, behold, two men stood by them in white apparel;
11  Which also said, Ye men of Galilee, why stand ye gazing up into heaven? this same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen him go into heaven.

 
While the disciples were "assembled together" (verse 4), when they were "come together" (verse 6), they took the opportunity, as was their custom, to ask Jesus the questions that were uppermost in their minds. At this time there was one predominant question: Was this the time when Jesus would restore the Kingdom to Israel?"
 
The reason for this question isn't hard to find. From the time of John the Baptist and the early ministry of Jesus Himself, the message had been going out that "the Kingdom of Heaven, the Kingdom of God is at hand". Why, the disciples themselves had been sent out preaching that message. Yet through those three and a half years, what was in evidence was the Kingdom of Caesar, and his deputies, kings like Herod the Great, Herod Antipater, Herod Antipas, Herod the Tetrarch. All these ruled under the sovereignty of the Caesar of Rome.
 
In fact it was under their authority that the governor Pontius Pilate delivered Jesus to be crucified.
 
Now Jesus, having died on the cross, and having been buried for three days and three nights (fulfilling His own prophecy and the sign of Jonah), had risen from the dead, in a transformed body, which had powers it didn't have before, like entering a closed room, and disappearing after their conversation. 
 
Surely this transformed Jesus was going to put an end to the evil Empire of Rome, and restore the Kingdom to Israel. But this would also be a transformed one: it would be, as Jesus had often preached, the Kingdom of God, the Kingdom of Heaven.
 
They were so sure about it, that all that they wanted to know was whether the time had arrived for its inauguration.
 
Jesus answered, but not as they expected it. He said it was not for them to know, because this was something that His Father had put in His own power.
Instead, they should be focused on what they themselves had to do, which was, first, to wait in Jerusalem, to be baptized in the Holy Spirit, upon which they would receive power, and be transformed into powerful witnesses. As such, they would witness about Jesus' Resurrection in Jerusalem and beyond, radiating out to the uttermost part of the earth ... something that, I'm sure, boggled their imaginations!
 
In the midst of that wonderful time of conversation, Jesus began to rise into the air, before their astonished eyes. Further up He rose ad further, until a cloud hid Him from their sight.
 
Now they were leaderless. Peter had often acted as leader of the group, but he had never displayed the courage and steadfastness that would surely be required at this time.
 
But the Lord did not neglect their question. He appointed two angels to speak to them after His ascension, and they told the disciples that Jesus would be returning, in the same manner that they saw Him go, that is to say, the time would come when He would descend from the skies and His feet would touch down upon the Mount of Olives from which He had just ascended.
 
The disciples must have understood that their question was answered at last. The Kingdom would be inaugurated when Jesus returned. But there were things for them to do. Return to Jerusalem, wait for the promise of the Father, and be baptized in the Holy Spirit, be transformed into powerful witnesses, and fan out witnessing about the Resurrection of Jesus to the uttermost part of the earth..
 
After their baptism in the Holy Spirit in Acts 2, towards the end of the chapter, we find them continuing with Jesus' regular practice: teaching (now they were the teachers), conversation (fellowship), discussion, answering questions, having meals together, and praying as Jesus taught them to pray.
 
Acts 2:42  And they continued stedfastly in the apostles' doctrine and fellowship, and in breaking of bread, and in prayers.
46  And they, continuing daily with one accord in the temple, and breaking bread from house to house, did eat their meat with gladness and singleness of heart,