@_elena Things I know:
A little spritz from a spray bottle provides an appropriate amount of water; or, if you can find a smooth stone with a slant to the top, that will help her find her right depth of water in a water dish. A bit of mud in another dish can help provide minerals & grit she may need. Aphids are what freshly-hatched juvenile ladybugs (the larvae, or maybe they're instars?) love to eat, so maybe invite your grown-up lady bug to inhabit any aphid-rich plants you have in the house.
*Thing I don't actually know:
What grown-up ladybugs eat