Please give us a link to the wiki on which this extension is said to be working.
Topic on Extension talk:Genealogy
It's running on https://archives.org.au — I only haven't put it in this page yet because it's a bit of a shambles at the moment! I'm still investigating the best way to do things, and at the same time am importing info from WeRelate (where I used to add stuff).
But feel free to have a crack at it there! You can register with the dreadfully secret word 'preservation'. :)
OK, I found three, via Wikiapiary. One obviously genealogy in USA, the other two clearly linked to Sam in Australia but only one having much genealogy in it. https://freo.org.au/wiki/User:Samwilson is Sam's user page on the one seeming to have least genealogy, but it does have a 3-month-old "People" category with potential for genealogy probably related to Template:Person. Site is currently very short of "Help" pages. Onwards and upwards, Sam!
Oops, I started drafting the above before Sam's reply. I wonder whether the apparent lack of "preview" means one cannot see potential edit conflicts??? Good work, Sam.