I don't know how to use this mod
How do I use it?

Spawn a half life 2 NPC shoot them until they are stunned and when youll get close enough press the use key ( E is the default use key) Stunned npc's are blue when youre too far and they are orange when youre in range.
I hope it helps

how do you use a crowbar kill?

Crowbar kills arent a feature yet

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Is there a way to disable health dropping on burn?

Im pretty sure there is. Just look for GK2 in options or utilities

Unless Delta took out the options