nice model, it fits the game well

on combining existing ones, it's something that's part of learning blender. but i used a method that's also useful in making avatars for vrchat. using the CATS blender plugin, you can combine models that have armatures/meshes together since it has a function for that. but you'd still need to re-rig and rename some bones and meshes as not all models are made the same.

i mean a guide on combining existing ones

if making it from scratch, you'll start off learning blender (which includes rigging and making the model). since i'm just using already-made models that were ripped/imported from games, it cuts some of the work but i still had to learn a lot to make the customization i wanted.

as for putting it into l4d2, there are some videos on youtube and a tutorial by Splinks that helped with learning that part of modding. honestly, googling the issues *mostly* helped.

is there a guide on making models like this?