1) Download phpWiki from http://phpwiki.sourceforge.net
2) Unzip it where you want it to reside finally.
3) run phpMyAdmin and create a new, empty database named e.g. "mywiki"
4) open the fille "schemes/scheme.mysql" from the phpWiki installation in a textfile and copy it to the clipboard.
5) in phpMyAdmin: Choose to enter a SQL statement and execute the code from your clipboard.
6) make sure you have a db-user which is allowed to read/write this wiki-db.
7) in the phpWiki-"lib/config.php", search for "mysql" and enter all necessary information (username, password, database, ...)
visit the phpWiki index.php and enjoy.