Can someone help and explain what this means on a car as I don't fully understand what it is thanks.

I take it it's running the fuel pumps after a filter change (etc) to purge the air out of the fuel system to save damaging the high pressure fuel pump by running dry.
Some will say they have done it without problems but others and the service manual will recommend running both pumps by either running a live feed to them or there is a facility in VCDS to do it.

Purging is a generic name for any process that involves pressurizing a system with one fluid (gaseous or liquid) to expel another, usually unwanted one.

In car maintenance context it may refer to fuel, coolant, windscreen/headlamp washer or brake system, although in the latter case the term bleeding is commonly used.

Considering the available info, I can't be more specific.