First, it would be a good idea to figure out a training treat. This can be relatively easy to do. If Justice is on a seed based diet, then figure out what the first 3 items are that she eats out of her food dish are. Then, remove those 3 items from her diet. They will then be a highly valued food reward.
If she's on a pelleted diet, then you can use seeds and nuts for her rewards. Dried fruits can also be another training treat.
The reward should be small enough that she can eat it quickly and not get full of eating fast. One person was cutting up a sunflower seed into 6 individual pieces for an umbrella cockatoo. Tiny rewards! But it also must be big enough for your bird to be willing to work for it.
As far as stepping up, here's something I wrote for someone else on how to teach step up.
Instead of having step up be "one step" (i.e. bird steps up), make it into 10 steps.
1. Reward bird for looking at you.
2. Reward your bird for moving his head towards you.
3. Reward your bird for taking a step towards you.
4. Reward your bird for taking another step towards you.
5. If he doesn't run away, keep rewarding him for remaining where he's at. (if he runs/backs off, you may need to start over again)
6. Reward your bird for taking a couple more steps closer.
7. Encourage him to come closer yet again and reward him.
8. Reward your bird for touching you with his toe(s).
9. Reward your bird for putting a foot on you.
10. *JACKPOT REWARD* Give your bird lots of goodies for putting both feet on you!
BTW, you can train this from inside the cage or even from the top of the cage. Choose one area and work with him from there. Once he understands the name of the game, then work on step ups from other areas of his and your home! Just because he learns to step up from inside the cage doesn't mean he knows how to step up from on top of the cage.... or that he knows how to step up from furniture inside your home. As far as your bird is concerned, all of these cases are separate, regardless of the behavior you are asking. Birds don't always generalize the behavior they learned in one circumstance with other areas. You need to teach them to generalize by teaching a new behavior in various locations, once they understand the behavior in one location.