With a minimum of effort (ahem...Wikipedia), we can obtain background info about Acts that we might not have if we limited ourselves to reading just the NT:
Luke 24:51 And it came to pass, while he [Jesus - ed.] blessed them, he was parted from them, and carried up into heaven.
52 And they worshipped him, and returned to Jerusalem with great joy:
53 And were continually in the temple, praising and blessing God. Amen.
Acts 1:1 The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
2 Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen:
3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
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.
Thus, Acts Chapter 1 continues the narrative from Luke 24 that ended with Jesus’ resurrection and ascension. Acts begins by recapping the reappearance of Jesus to the disciples, adding some words and commandments that set the scene for the work that the Apostles will undertake. And we experience the Ascension for a second time:
Acts was read as a reliable history of the early church well into the post-Reformation era. By the 17th century, however, biblical scholars began to notice that it was incomplete and tendentious – its picture of a harmonious church is quite at odds with that given by Paul's letters, and it omits important events such as the deaths of both Peter and Paul. The mid-19th century scholar Ferdinand Baur suggested that Luke had re-written history to present a united Peter and Paul and advance a single orthodoxy against the Marcionites. (Marcion was a 2nd-century heretic who wished to cut Christianity off entirely from the Jews).
We are also treated to a second (differing) recounting of the fate of Judas, the establishment of “ordainment” in order to “be a witness” to the resurrection...
9 And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight.
...and the casting of lots to choose Matthias as a replacement in the Apostles for the dead and disgraced Judas.
22 Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection.
It has been noted that the casting of lots for Matthias is similar to the lottery of Ajax found in Homer’s The Iliad ... And that Homeric parallels will continue to be apparent throughout Acts.
Chapter 2 is all about the Pentecost - the descent of the Holy Spirit upon the Apostles. This would have you believe that the Apostles are now imbued with the power of God just as Jesus was, and thus authorized as God’s delegates to spread the good word. Depending on your attitude about such things, you might consider this your direct link to the Almighty, or the most sinister words ever written. You decide! So, Peter exhorts his brethren to repent and accept the spirit, thereby marking the beginning of “the church”.
As mentioned a little earlier, Acts appears to be harmonizing the theological views of Paul and Peter, which apparently differed. At the moment I write this, I’m not knowledgeable enough about the two theologies to comment on their differences, but it will be interesting to see how this plays out.
In Chapter 3, Peter heals a lame man in the name of the Lord, and preaches to the onlookers about how having faith will bring you His blessings ... Or lots of presents at Christmas.
Chapter 4 sees Peter and John accosted by the Sadducees and the authorities for preaching, which gives them an opportunity to do more preaching. I expect this theme of oppression and evangelizing to the oppressors (and onlookers) will be quite prominent.
These first Chapters in Acts set up the Church, establish the mission to preach, and demonstrate (presumably) that there will be haters, as in Chapter 4, and that the Apostles will take advantage of these attempts at oppression to further spread the word.
Did I mention preaching?