Are you trying to install Dokuwiki on to a webserver from a web host provider or are your trying to install it onto your computer (localhost)?
If you are trying to install it onto a computer of yours, you are going to need an AMP. It is a web server stack that has everything you need to run a website from your computer. But no one is going to see it over the internet. There is Wampserver for Windows and Xampp for Windows/Mac.
For local development I use Xampp.
Here are the steps to get dokuwiki running after you install the software on Windows.
1. Go to My Computer/This PC > Local Disk (C:) > xampp > htdocs
2. Open the dokuwiki download, mine was a .tgz
3. Copy the dokuwiki folder to htdocs
4. Open your internet browser and type in
http://localhost/dokuwiki/install.php
5. Follow the steps for the install. And thats pretty much it.