Adding props in Hammer to map

I have some props in Garry’s Mod that i want to put into a map I’m making, but I have no clue how to add props to the props directory. Come to think of it, I can’t add Portal or Team Fortress 2 props either, just Half-life 2/episodic props, so if you know how to do that please post that too. I need EXACT instructions on how to do this, such as where to drop the model/material files and where those folders are, or what I’m supposed to do period.

For custom models (and why not TF2/Portal too? Extract the files from the GCFs), just drop the folders “models” and “materials” (that come with the custom models you have) to your Episode 2 directory.
If you’re using the Ep2 SDK config, it should load all the custom models and textures from there.

Usually Gmod addons, that include models, come in the “addon” format. That means the files are inside a folder, usually named the same as the mod.
Take the folders for the models/textures from that folder and copy them.

Link to the program used to extract GCF files in the post below.

Here’s a link for GCFScape

I monkeyed around and figured which episode 2 directory it is, username/ half-life 2 episode 2/ep2, but I did have to make the models/materials files.

Please read.

Thank you for the link Bulaba0, very informative. Thanks for the link to GCFScape Zally13, but it was a broken link. I still found a download site though.