Probably the best way to learn how to use a signal event is to look at the blog posts that Niall Commiski from Amis has written.
Oracle BPM 11g Signal Events and Oracle EDN – Part 1
Oracle BPM 11g Signal Events and Oracle EDN – Part 2
I doubt you'll find the documentation very helpful, but here it is: http://docs.oracle.com/cd/E28271_01/doc.1111/e15176/ipc_bpmpd.htm#BPMPD733
There are a few moving pieces to this, so you might need a little help if you run into an issue getting it to work. Ping the forum again if you run into problems getting it to work.
Hope this gets you going,
thank you very mutch. your likns are helpfull.