You need to add the appropriate server plugin. For example, if you are using a JBoss server, you need to add the JBoss IDE plugin. Look up on the net for the plugin based on which server you are using.
Eclipse comes with a tutorial for debugging JSPs: Help | Help Contents, then Web Tools Platform User Guide | Using the Server Tools | Application Testing and Publishing | Debugging Applications On a Server
Also, do not look for or install JBoss IDE - that is an old product no longer supported. Instead, use JBoss Tools: http://www.jboss.org/tools