How to install Emacs source code under Ubuntu
Only one command:
sudo apt-get install emacs24-el
How I locate that package emacs24-el:
sudo apt-get install apt-file;sudo apt-file update;
apt-file search help.el.gz
BTW, I assign hot key "C-h C-f" to command "find-fuction" which "Find the definition of the FUNCTION near point".