Thank you for answering! I love your posts about rats. I think it's critical people see them as tremendously lovable, but not to be adopted on a whim.
Usually my daughter will put a favorite treat, often a dab of a vegan yogurt of some kind, on a spoon and hold it just out of reach with her right hand, so the rats have to climb onto the left hand to get it. Eventually they are comfortable just climbing right onto her hand, but it's a slow process.