Sorry to hear you are having issues. Please use this link for Icons Pack https://www.wincustomize.com/explore/iconpackager/search/ I just download some icon packs and all of them installed with no issue. Some come with xxx.ip extension, which will install itself by just download it and double click on it. Some of it come with xxx.zip files which usually work if you rename those files from xxx.zip to xxx.ip and do a double click on it. And if you have any that do not work. You can simply put in a comment on that icon pack comment section and ask the icon designer on how to install his/her icon package. Or PM them for help.
As for the user manual, I have forward your request to the Stardock Support Team for their review and recommendations. We really do appreciate your feedback, Thanks
Stardock Community Assistant.