[BGEE Mod] Improved Gnoll Stronghold - Help needed

This mod adds:
-A challenging Gnoll Overlord between the upper pits of the Gnoll Stronghold
-Textscreen and artwork for the Gnoll Stronghold upon entering first time (artwork to be finalised)

I wish for the Gnoll Overlord to say a single line to the PC and then attack.
I have gnoll_x.bcs call gnoll_x.dlg (which is compiled from gnoll_x.d)
I have spent two days trying to decipher the many guides and weidu tutorials available to no avail in finding a solution to why my code doesn't work.

I have attached the files in a zip.
Please can anyone help out?

1. Why does this code from the .d file not even make the Gnoll Overlord say the line when he sees a party member?

BEGIN gnoll_x
IF ~~ THEN BEGIN block1
SAY ~The weak will perish!~
IF ~~ THEN EXIT
END

2. Why does the below code to speak and attack not compile from .d to .dlg dialogue file?

IF ~~ THEN BEGIN block1
SAY ~The weak will perish!~
DO ~Enemy() Attack(Player1)~ EXIT
END

3. Isnt the IF ~~ THEN on 3rd line below pointless despite it not compiling without it?
[spoiler]IF ~~ THEN BEGIN block1
SAY ~The weak will perish!~
IF ~~ THEN EXIT
END[/spoiler]

4. Fundamentally, when exactly are "BEGIN xyz", END, EXIT and "IF ~~ THEN" used please?

Many thanks