Question

who was the first potgieter to set foot in south africa

Answer 1

See WikiTree question: https://www.wikitree.com/g2g/39709/who-was-the-first-potgieter-to-live-in-south-west-africa

Other sources on the internet:

https://www.genealogieonline.nl/en/stamboom-potgieter-en-de-koker/R1104.php

https://en.wikipedia.org/wiki/Potgieter

http://www.genealogytoday.com/surname/finder.mv?Surname=Potgieter

Answer 2

You can have a look at his Wikitree profile at  https://www.wikitree.com/wiki/Jansz-250.

There is also some information about him on "First Fifty Years - a project collating Cape of Good Hope records" http://www.e-family.co.za/ffy/g5/p5283.htm