I wana put forums on my website?

You need to get (paid) hosting which offers forums.

I recommend one of these: http://www.hosttell.com/

Powweb has the best offer right now. It's on a 50% sale - $3.88/month ($46.56/year), and you get a free domain from them. (like www.yourwebsite.com)

They include easy, one click install of phpBB forums.

These two people recommend phpBB but am starting a web development website in which I'll have a forum between other things and after some testing I decided to with SMF instead of phpBB, you should test both.

This is SMF

http://webhole.net/forums

this is phpBB

http://webhole.net/xforums

If your web host supports PHP and MySQL, you can download a forum package such as the free phpBB or buy the more popular vBulletin.

Then, you have to upload all the files using FTP, if your web host supports it.

There are usually instructions included with the download.

You need to have access to a SQL database and your website must be able to run PHP pages. If so, you can install phpBB onto your website.