You say Linux 10, and reference yast, so I assume you are running openSUSE or SUSE Linux Enterprise. Linux is the kernel, and on top of that is everything else. Just a note so when you ask another question, people may need to know what you are using...
The command is working both ways. The function of the ampersand is to make a command run in the background. So that should answer 1 and 3. As for 2, I am pretty certain that number represents the process number. The ps command will show you running processes and the process number, the kill command followed by a process number will stop that command.
And finally, welcome to LQ!