[Vwdiesel] installing block heater - tips?

[Will Taygan]

1991 Jetta ecodiesel.  I've got the VW/zerostart freeze plug block
heater, and I'm a bit nervous to whack at the old freeze plug to remove
it.  How dangerous is this? any tips?  How much space is the behind the
plug before I get to the other side of the coolant jacket.

Also, I need to read the instructions again, but it says install at 12
o'clock (I think - or maybe it says 6), but how do I know what's 12 an
what's 6?  Loop up or down..  I'll figure it out (I hope)

Will.