Walkzee is a game in which you walk around IRL and tap on a map to pick up dice. Put those dice into dice-poker hands. The big green square is a map showing dice 1000m in each direction; you can pick up dice up to 500m away. If you can't pick up a die because it's too far away, walk closer.
Walkzee uses your phone's "GPS" (geolocation) to know if you walked closer. On Android, it'll ask for permission. On iPhone, it will silently fail unless you turn on Location Services. If you're thinking Why does it say "big green square" when I just see a big white square?, that's because your phone is failing at geolocation, alas.
Tap a die to pick it up. You can put it down in a hand or in the stash area. Hands are like quests or missions. You're trying to complete dice-poker hands. Complete a hand and you can press the 🏆 button to exchange the hand for points and get a new hand/quest/mission/thingy.
You need five dice to complete a hand. If you're working towards a 2x1️⃣, have those two dice and wonder why the 🏆 button is still grayed out: You need three more dice.
Normally the game checks your location about once a minute. Don't want to wait a minute? Press the ⌖ button.