To begin with, a 30 page site is pretty huge. Many small businesses run very effectively on 5 or 6 pages (Home, About Us, Our Services, Our Products, Contact Us and so on).
Filling 30 pages is no mean task and you'd be better off trying to make half a dozen vibrant pages populated with interesting text and crisp accompanying images than thinking along the lines of 30 pages plus. Start small and let it evolve, ut don't aim high to begin with until you are comfortable with the technologies and methods used to produce your site.
Now, you have a couple of hurdles to overcome from the outset. Forums tend to rely on dymanic pages running, for example, as PHP with an underlying MySQL database or via CGI. Finding a web host who will offer you the features you need for free will be your first major obstacle and I will let others suggest possibilities on that front since I never try to keep tabs of who is offering such accounts. Most free providors won't offer you MySQL although some may offer PHP, and few offer CGI support either. Web hosts want to make money the same as any othe business and you can get entry level hosting from around £25 per year.
Next, you say you want everything for free with no trial versions. That's a lot to ask, especially if you want a visual WYSIWYG web editor. The best bet is to look through computer magazine cover disks for web and image editing software. PC Advisor recently gave away a full version of NetObjects Fusion MX which would be a pretty good starting point for you, and most magazine cover disks have image editors. IrfanView is used by many for image processing and is free click here and could be worth a look.
SmartFTP for FTP (File Transfer Protocol) is free for personal use click here
HTML Kit is a superb code editor and is free to use. It has more features than you can shake a stick at and I always recommend it if you don't mind working with code click here
Have you looked at what you already have on your commputer ? If you have Microsoft Office you may have FrontPage installed with it, and if so you already have almost everything you need to design great websites.
For information on forums you could look at phpBB click here YaBB click here and YaBB SE click here
I wish you the very best of luck and if you come ustuck you can always ask questions in here, but I doubt you wil find everything you need entirely free.