Compiling new animations for valve biped in GMOD?

Hi, so how would somebody go about creating new animations for playermodels to use in garry’s mod? I know its possible because of the prone mod (however, he may have used a lua animation library…)

Specifically, I’d like to create new holdtypes for weapons, and compile them for the valve skeleton so all playermodels can use them. How would somebody do this?

Any guidance, reply, or help is appreciated. Thank you!

Putting in my grain of salt because I really want to know this too, I know that you can make sequences for playermodels, and use them for animations, but I know there’s much more to it, aimlayers, octo directional movement, more than the maximum crowbar animations! If only there was a tutorial for all this stuff, usually it’s just a vague response.

EDIT: Actually answering the question, the prone mod has his own .mdl (like m_anm.mdl) from what I know, you can try to make animations, compile them together and play them using LUA.