How does one set up a soak? Is a critter tote ok? And if so how much water is needed?

I'm just nervous because obviously she is rather shy right now and that article said she could even get aggressive...currently she's poking her head out so maybe she'll get the rest by tomorrow by rubbing around

And I know my humidity is low as I mentioned in the main post, it's been better than the past but it still fluctuates...