What does this sentence mean?(HELP DON'T UNDERSTAND)?

Question

Okay well I'm doing a research report on the War on the Mississippi-Grant's Vicksburg Campaign-and there's this group of sentences that don't click in my head! I don't get it! It's in this book and the sentence says--
"By early June 1862, with the capture of NewOrleans and the neutralization of Fort Pillow, about 50 miles north of Memphis, the Union had a firm grip on the Mississippi at both extremes of the Confederacy. But the center remainded in Confederate hands. And the focal point of Rebel resistance was Vicksburg"

I'm not understanding it exactly. Can you tell me what it means or help me better read and understand.

Answer 1

The North controlled the southern end of the Mississippi from Baton Rouge/New Orleans south to the Gulf of Mexico. They also controlled the northern end of the river from Minn. to Memphis after the capture of Fort Pillow made Memphis impossible for the South to Hold. The only section that the South still controlled was the area around Vicksburg Mississippi. The North started operations to take Vicksburg and cut the confederacy in 2.

Answer 2

The good guys (Union) had just captured the edges of the bad guys' (Confederates) territory along the Mississippi River. The Rebels (Confederates) still had control of the middle of the Mississippi river, though. The Rebels were trying to keep Vicksburg theirs (I think.)

Answer 3

Do a search on Vicksburg right here on Answers. You will find an explanation, I know because I put it there.