I have a project that has complicated physics and I can’t find the information that I am looking for. It might be easier to look at everything until I find what I need.
For starters I’d look at the documentation and content examples.
I believe they did a few livestreams on it as well which you can find on YouTube. =)
And depending on how complex your physics is, it might be best to use your own physics engine. Unreal physics are implemented very deeply into the rest of the engine and it has its quirks (variable time steps being one). The Rocket League devs used Bullet because they needed full control of the physics simulation, check out their GDC talks.
I agree with the comments above. You’re own physics engine would be the most beneficial as it is tweaked to your needs.