I just installed Lubuntu on my laptop and installed Pjsip on my lubuntu .
For compiling purposes I need to locate the PJSIP library but I don't seem to be able to locate them or other system files for that matter.
In my file manager only Desktop and Documents appear and some other folders which don't contain any of the installed files.
In Ubuntu it was easy there was an computer icon where I could browse through all the files i had installed.