When I asked Assistant for help navigating the Chrome OS UI:

Q: How do I disable Assistant?
A: [points me to results on disabling Assistant on Android]
[and suggests "How do I disable you?"]

Q: How do I disable you?
A: [more results for Android]

Q: Turn off the lights
A: It looks like those lights haven't been set up yet. Just open Assistant settings and go to Home Control to add lights.

Q: Where do I find Assistant settings?
A: [points me to Android Central]

Q: What can Google Assistant do?
A: [couple suggestions, including "Email Rachel"]

Q: Email Rachel
A: To do that, you'll need to install Gmail
[links to Play Store]

Q: How many gigabytes do I have?
A: [provides advice for iOS users]

This is on eve R66-10368.0.0 canary.