3-6 - God calls Samuel; Eli doesn't hear God anymore. The Philistines capture the ark; Eli and his sons die. The Philistines are persecuted by God Himself until they return the ark, but Israel also sins when it returns.
7-8 - Samuel judges and prays for Israel, and they defeat the Philistines. Later when he is old and his sons are disobedient like Eli's, Israel asks for a king. This is not right, but God gives them what they want for His own purposes and their judgment.
9-11 - God brings Saul to Samuel, who anoints and instructs Saul as king. Samuel gathers all Israel and introduces Saul. Saul defeats the Ammonites in battle.