How to change swim/underwater speeds?

Those settings are used for swimming. You'll want to create a new state which adjusts them when the speed change ability is active. This is how the demo scene does it.
When the swim ability is active you can use the state system to change the acceleration values on the locomotion component.
having problems understanding states i guess.

So I click on swim
and I create a state under swim called swim movement?
then what property do I add? I have a non root motion character.
Take a look at this page: