She cannot understand? Liar....can she read English then. Tell her to go to the agent and tell the agent to teach her what she should or should not do. Write a list for the agent first, let the agent give the list of dos and don'ts to her and ask her if there is anything she does not understand. The agent probably has a staff who can translate, or there are other maids there who can. There is also google translate online, so she cannot pretend not to understand.
New comers are easier to change, don't let her become old seafood, then she will never change.Better include she cannot use your cosmetics or other personal products. One of my maids in the past used my face cream!!