Extreme Noobish question but still need your help

Before I say anything if you think my question is stupid than dont post about it, I only want some answers and if you dont like it than GTFO

QUESTION: How do I get my left 4 dead 2 models in garry’s mod

Do you have left 4 dead 2?

L4D2 is not supported. Go find a model pack on gmod.org.

You can’t unless you know how to port.

I suggest going to http://www.garrysmod.org/downloads/ and have a look around there.