Realtime mesh deformation collisions in Unity 5

[info]

I am a total beginner of editing meshes via script

I would prefer JavaScript but c-sharp will work too

I use Unity 5

My target platform is windows,mac and linux

I might publish my game to mobile later

I Dont want to pay for assets like Impact deformable Because they ALWAYS Turn out to be useless later

My question is:

How to deform (For example a car) a mesh through collisions and I would also appreciate some links to tutorials or some explanation because I don't want to copy I want to learn. I dont want the Complicated stuff just how it works and how to do it and basic stuff

Here are the links which I tried but found useless

Catlike coding

Impact deformable

Meshinator

Mesh deformation on impact