Tennis Ladder can notify you when someone challenges you, confirms your result, sets a match time, or when your league has news.
In the iPhone/Android app: allow notifications when asked (or tap the bell icon any time). You'll get a push straight to your lock screen.
On the web: the same bell icon turns on browser notifications — works on desktop and on Android. On iPhone, add the app to your Home Screen first (Share → Add to Home Screen), then enable notifications from inside it.
Email: important things (challenges, confirmations, weekly digests) also arrive by email, so you're covered even with pushes off. Every email has an unsubscribe link for the digests — match-critical emails stay.
The Monday club email: every Monday morning you get your club's week in one email — last week's results, your position, and what's coming up this week so you can come down and watch. Big matches (top-of-the-table clashes or ones your organiser stars) also get their own "save the date" email a couple of days before. Organisers don't need to switch any of this on — it's automatic for every club. You can mute big-match alerts in Settings, or unsubscribe from the weekly email with the link at the bottom.
Not getting pushes? Check the bell icon shows they're on; check your phone's notification settings for Tennis Ladder; and make sure you're signed in on that device. Turning the toggle off and on re-registers the device, which fixes most gremlins.