Opformark

Hello all, hoping you can and won't mind helping a newbie! I have a 97 GTI and it surprisingly doesn't have a flush adapter on it. So, I got one this week and the directions are cage at best. So, do I T it in to the hose that shows the arrow into the head? Or the short hose between the head and pipe? I know the running before water and water off before engine off rule, just not sure where the t splice goes on this 717.
Many thanks!!

Opformark

Anyone?
I did find a pair of coolant lines on the back side of the head, marked flow by arrows so I'm thinking it goes in the hose marked with flow into the head. I might just put it in there, but would like someone to confirm that please.