wordpress and punbb problems

Right done a fair bit of searching on Google, for info on putting the theme around the forum, and found this:

https://www.liewcf.com/blog/archives/2005/04/integrate-punbb-forum-into-wordpress

But the what part of the css files are needed with the header and footers, or does the whole bit go in? Sorry but I’m fairly new to all this.

Thanks