Where Are the Models

[LUNDAYY]

over time I have proven to myself that I am not as good with computers as I would like to be and even though I have spent a lot of time using sfm I am VERY inexperienced.

I would like to edit the medics Ze goggles using blender for a dr horrible video so I just want to shorten one lense and maybe bring up the scale but I can't find the file.
I watched helljumpers tutorial but I don't have the folder called sourcesdk_content which is where he got his files
I'm not sure what I'm supposed to do I have GFC scape and mdldecompiler if I need to decompile it but there isn't a way without knowing where the file is located I have both sfm and tf2 so i'm not sure where I should look and what should I do?