Android: download and install the Grove app directly — no store account needed. Your phone may ask you to allow installs from your browser, which is normal for apps distributed outside the Play Store.
iPhone and iPad: open Grove in Safari, tap Share, then Add to Home Screen. You get the full-screen app with its own icon and notifications. The App Store version comes later and you lose nothing in the meantime.
Open Grove · Grove · Features · Pricing · About Grove