It's worth pointing out that we're all volunteers here and any urgency you have is not shared. In fact, demands such as "Urgent help" will often put people off helping you out at all. It's just not fun.
Now, back to your question. What have you tried so far? Have you read the jforum installation instructions on jforum.net? I'd say that would be a good place to start. What specific thing are you having trouble with just now?
The JForum version on jforum.net is obsolete, and has numerous bugs and security issues. It is now being developed as "JForum2" on SourceForge, so ready-to-install war files as well as instructions for manual installation, can be found somewhere around https://sourceforge.net/p/jforum2/wiki2/browse_pages/