Hello Chand, your anwser is incorrecto, because "Phpfox::getUserId();" is de logged user, not de profile user. The question is How can i get the user id of a profile User (ie. index.php?do=/profile-7/) ?
We have a user guide, the knowledgebase. I have a downloadable admincp user guide in there too that though for v2 much is valid for v3. I also have my script techs site with detailed written tutorials and video tutorials. The tutorials are out there, you just need to find them. I have a link to the kb table of contents you should bookmark, in my signature, and a link to my site.