It is very simple to install PHPBB forum. Please check the installation procedure
FYI: You just need to have mysql DB, and its credentials for this.
**Decompress the phpBB 2 archive to a local directory on your system.
**Upload all the files contained in this archive (retaining the directory structure) to a web accessible directory on your server or hosting account.
**Change the permissions on config.php to be writeable by all
**Using your web browser visit the location you placed phpBB 2 with the addition of install/install.php, e.g. http://www.mydomain.com/phpBB2/install/install.php, http://www.mydomain.com/forum/install/install.php etc.
**Fill out all the requested information and hit Submit( The information is nothing but you need to supply mysql credentials that's it.
**Change the permissions on config.php to be writeable only by yourself
**Click the Complete Installation button or revisit the location you entered above.
Once you have succssfully installed phpBB 2.0.x you MUST ensure you remove the entire install/ and contrib/ directories. Leaving these in place is a very serious potential security issue. And try to keep your forum version uptodate inorder to avoid various threat's.