Please read the getting started documentation in the documentation section of this site.
Thanks... I have read that manual before... but that wasn't enough...
Let say your .jar is abc.jar and your .war file is abc.war
After deployment you shall have the abc.jar and the abc.war in the JBOSS_HOME\server\default\deploy. (if you do not, then copy the two files in there).
When you will start the JBoss, the abc.war will have a directory in JBOSS_HMOE\tomcat-4.1.x\work\MainEngine\localhost\abc and you do not have to worry about this.
All you have to do after deployment is to put the abc.jar and abc.war in JBOSS_HOME\server\default\deploy directory.
After that, you can try http://localhost:8080/abc
I am sure this information will help you