The required parameters are the PhilPapers label (category, or journal) and the PhilPapers topic both of which appear in the url for that topic. The template then uses the Wikipedia article title as the link text:
* {{InPho
| {{{1}}}
| {{{2}}}
| {{{3}}}
}}
{{{1}}}: category, rec, search, or journal
{{{2}}}: PhilPapers topic
{{{3}}}: Alternate link name (if this value is empty, it defaults to the article pagename)
Suppose you want to add an external link to the PhilPapers'category on Aristotle. Locate the article at the PhilPapers website. The url will contain a number. Enter this number as the second perimeter.
Note: This template should generally only be used in the External links sections of articles; it should not be used in citations, references or bibliography. Consider using {{citation}}, {{cite web}} or related templates for those purposes.