It is frequently observed that God is the central character of each book of the Bible - and the author of Acts is quick to remind us that, even though Jesus ascends to heaven in chapter 1, it is still His story.
He does this in three ways. First, Jesus does not ascend to heaven at the end of the Gospel of Luke (which would have been a more natural conclusion to that book), but at the beginning of Acts, so that we will remember that He is still the star. Second, Jesus is the one to deliver the outline for the book - “...you will be my witnesses, telling people about me everywhere - in Jerusalem, throughout Judea, in Samaria, and to the ends of the earth.” (Acts 1:8 NLT) - which reminds us that the other characters in this story - the apostles - are doing His work, fulfilling His mission. Finally, He promises the Holy Spirit, who will be an active presence throughout the text, guiding and empowering the disciples.
It is also helpful to remember that this story is our story as well. The mission Jesus gives His disciples - to carry His word to the ends of the earth - is our mission as well. As if to emphasize this fact, the first story after Jesus’ ascension is about replacing a disciple. This is the first time the church has dealt with this issue. It is not the last. Every disciple - including you - stands in the place of another who has gone on to meet the Lord. Each of us will one day pass the torch to another. The mission continues, generation to generation.
As you read Acts, draw inspiration from the brothers and sisters in Christ who have gone before you as you carry out the mission our Lord has left for us.