YaBB 2 Quick Installation Guide - Installation 2
Introduction
Before starting
Installation 1
Installation 2
Installation 3
Setup
In your 'cgi-bin', create a directory called "yabb2" (or whatever name you wish to use). If you do not have a cgi-bin, then first create a directory called 'cgi-bin' and then inside that create the 'yabb2' directory. The example structure is provided in the YaBB package you've downloaded.
You should have a folder structure similar to the following:

    	cgi-bin/yabb2/
    	cgi-bin/yabb2/Admin
    	cgi-bin/yabb2/Boards
    	cgi-bin/yabb2/Help/English/Admin
    	cgi-bin/yabb2/Help/English/Gmod
    	cgi-bin/yabb2/Help/English/Moderator
    	cgi-bin/yabb2/Help/English/User
    	cgi-bin/yabb2/Languages/English
    	cgi-bin/yabb2/Members
    	cgi-bin/yabb2/Messages
    	cgi-bin/yabb2/Modules/Digest/Perl
    	cgi-bin/yabb2/Modules/Time
    	cgi-bin/yabb2/Sources
    	cgi-bin/yabb2/Templates/default
    	cgi-bin/yabb2/Variables

Then, in a section of your webspace (outside the cgi-bin, generally in a 'public_html' or 'htdocs' folder, as suggested in the package's folders), create another directory called 'yabbfiles'.
You should have a folder structure similar to the following:

    	yabbfiles/
    	yabbfiles/Attachments
    	yabbfiles/avatars
    	yabbfiles/Buttons/English
    	yabbfiles/ModImages
    	yabbfiles/Smilies
    	yabbfiles/Templates/Admin/default
    	yabbfiles/Templates/Forum/default