Have you submitted a support ticket yet? Are support is free to assist customers with issues just like the ones you are experiencing.
The documentation covers everything a typical setup would require to get PowerCMS functioning properly. We have had many customers succeed in implementing PowerCMS without any issues with the documentation.
You should not have to edit any files other than what is documented. However, since you placed your PowerCMS files in a subdirectory, the paths need to be adjusted. This is probably something that could be made clearer in the documentation.
As far as iRite goes, if you specify the settings correctly in the WA_Globals.php file, you should not need to change anything else. However, there is no way for anyone to determine the correct settings unless they look at your site and your server's configuration. This is why i recommend you submit a support ticket, if you cannot figure this out.
If there are specific areas where you think documentation can improve, please let us know by completing the contact form found here submit-idea.php.