The link to the Lioness app on the Google Play Store is here.
The app was recently reset by Google Play Store but is now back up. Depending on when you are seeing this guide it may not be indexed by Google/Google Play Store just yet (it used to be at the top of the search) but the direct link above should get you to it to download and to receive app updates.
If you are a Lioness 1.0 user and have an earlier version of the app, please also download this app to receive the most recent features and functionality and to keep getting app updates.