You can get templates for these types of things. Xoops I think is a Portal Template which uses Modules and Databases to get complete Dynamic Pages. Forums, like this, everybody uses templates for (all the ones with sense) - and unless you plan on making your own Forum then its probably best to use phpBB
which is free, or this which is vBulletin
which is around £40 for a year. There are some ASPX Forums around, ASPPlayground
for instance is a £120 one of fee - but you'll need far superior hosting to that of the PHP Boards.
You can read books for PHP learning - and eventually would will pick up Database and Dynamic uses for them.
If you can't get a three column layout though... you should learn more HTML before you get into PHP.