Chapter 12 Questions

I am doing a presentation on the plot and themes with a poster on chapter 12. Im just wondering about a few things..

1. How did Jack and his hunters set the fire? My friend said they threw a rock from a cliff into the thicket but I can't find the page that indicates that.

2. And do the boys appear in a line while they are searching for Ralph? I know they do on the beach.

3. Does Ralph also create a stick sharpened on both ends? My friend insisted on drawing it on, but I thought only Roger had that.

Thanks for the help.