A news lead in a story basically sums up the story in one to two sentences. The lead of the story has the action of the story and it tells you to who, what, when, and where.
This is the news lead from the Star Tribune on the story about the shooting in Cedar-Riverside Monday:
"Two men were wounded in a drive-by shooting Monday outside a bustling community center in Minneapolis' Cedar-Riverside neighborhood."
This lead includes the who (underlined), the what (bolded), the when (italisized), and the where (underlined).
The lead is specific enough for the reader to know what's happening in the story (like two men, and drive-by shooting), but not so specific that they have all the information of the story. The reader knows that the men were injured which is important, but saying that they were "wounded" is general so they would need to read on.
I noticed that the lead is just the most important information from the story, surrounded by graphic adjectives like "bustling".