For
litter training I always recommend the same three things...
1. Give them time - especially if it's a new bunny, or a young one. You wouldn't expect a baby human to be
potty trained, don't expect it from a baby rabbit either. Babies are messy, and that includes baby rabbits. Also, when rabbits are in new environments, they will often go to the bathroom all over the place, to mark their territory.
2. Get them fixed - most of the time it greatly improves their litterbox habits.
3. Make sure to keep hay in their litterbox - Bunnies like to multitask, they usually poo while they are eating. I only put hay in my rabbits litterbox, and no where else in the cage, because where ever they eat hay, they go to the bathroom. That means having to clean the litterbox alot, and I give my rabbits fresh hay twice a day - because they won't eat the hay they go to the bathroom on. But it's worth it, because then instead of having to clean poo and pee out of the whole cage, I only need to clean the box.
Good luck! Ruby is young, she'll learn eventually. You should have seen the messes Zeus use to make when he was a baby.