How do I can do physics engine

Hello!

I have a problem. I would like to create a physics engine in my platform football game. The problem is that i dont know how to do it. I was looking for guides but nothing I found. When I tested the demo something like this happens like in this demo I do not know how to fix it. I would like create fluid physics but i need your help. Sorry for my embarrassing English. Im from Poland and writing this post ministered to translator.

Here is something that might be what you are looking for:

I can't help you with the example. I only found the thread and thought that is what you are looking for.