dragon, I feel your pain.
It looks like you are asking two questions here:
1. How do I change the structure of my url's?
This question is a tad confusing on its face, as you stated you want to make your url's look like this
http://mywikiname.com/doku.php?id=page instead of
http://localhost/dokuwiki/bla-bla-bla
The way you are saying you want your url's to appear, is the default installation appearance, most folks want to get away from that format and have their url's appear as
http://localhost/dokuwiki/bla-bla-bla. Did you simply ask the question in reverse?
That being said, you will need root/dokuwiki access in order to change this url structure. There is a toggle to flip in the Admin/Configuration Manager/Advanced but in addition to flipping that switch, you need to alter the .htaccess file in your root folder where DokuWiki is installed.
So, by using Bitnami Cloud, I am not sure if you have that access, do you?
2. How do I make DokuWiki accessible to users?
Please read this page
https://www.dokuwiki.org/acl and study it, and this will show you how to make your wiki accessible to users, or not, or parts of your wiki accessible or not.
Let me know if you need anymore help or clarification.
John