The simplest method of installing DokuWiki on a remote host might be to use the DokuWiki Downloader. This is a single PHP script, that needs to be transferred to the remote host (eg. via FTP) and then be run in the web browser. It takes care of downloading the latest release of DokuWiki, extracting it and running the installer.
The script can be downloaded here: dokuwiki-downloader.php
DokuWiki will be installed in the same directory as the script. This directory needs to be writable by the webserver. Any possibly existing files in that directory (including a possibly needed index.php) will be overwritten by this script!
A detailed description along with screen-shots can be found here: Setup DokuWiki on Free Hosting in < 15 Minutes.
In order to use the script to update an existing DokuWiki installation, delete doku.php before launching it.1)