The key events from the beginning of To Kill a Mockingbird focus on Jem and Scout’s character development.
If you are creating a plot line of chapters 1 to 7 of To Kill a Mockingbird, you should include these events: Scout and Jem meet Dill, Jem goes back for his pants and finds that Boo Radley has mended them, and Boo Radley leaves gifts for Jem and Scout in the tree until Nathan Radley plugs the whole with cement.
When Scout and Jem meet Dill, the book really gets off the ground. Dill is the one who is most interested in Boo Radley, who becomes important to the children’s lives from that point on. The importance of this is demonstrated in Scout’s introductory paragraphs, when she explains where it all started.
He said it began the summer Dill came to us, when Dill first gave us the idea of making Boo Radley come out. (ch 1)
Clearly this event is important, since it is where things started.
Next, Jem going to get his pants is important. Scout and Jem have a disagreement about whether or not he should go retrieve his pants when he loses them on the Radley porch.
He blew out his breath patiently. "I- it's like this, Scout," he muttered. "Atticus ain't ever whipped me since I can remember. I wanta keep it that way." (ch 6)
Scout does not understand why Jem would risk his life, but the reader realizes that it is a sign of maturity that Jem does not want Atticus disappointed in him. When Jem realizes that Boo Radley has mended his pants to keep him from getting into trouble, we see a different side of Boo.
Finally, the various gifts the children find in the tree are important. At first, the children do not know who the gifts are from. When they realize that the gifts are overtures of friendship from Boo Radley, they are saddened when Nathan plugs the hole.
When we went in the house I saw he had been crying; his face was dirty in the right places, but I thought it odd that I had not heard him. (ch 7)
This incident demonstrates Jem’s empathy for Boo, which is not fully developed in Scout yet. Jem is more mature, and Scout is maturing.