Use the browser menu
Open play.justonemoreorbit.com in the browser where you want to play. In Chrome, Google documents the More menu, then Cast, save, and share, then Install page as app. An installation icon may also appear in the address bar. Follow the browser’s confirmation rather than looking for a mobile Home Screen button inside the game.
Other browser interfaces can differ. A missing install control does not prevent ordinary browser play, so keeping a bookmark is a workable fallback.
Give the game a comfortable window
Open the resulting app entry and choose a window size before starting a run. ORBIT measures the available area and adjusts its canvas to fit. A narrow upright window offers a different view from a wide landscape window, so keep the shape consistent while comparing your own attempts.
Click the game area when you want to direct keyboard input there. If a menu or share dialog is open, close it before expecting the game’s play keys to act on the forest.
Understand what has changed
The desktop entry still runs ORBIT’s web game. It does not create an ORBIT account, synchronize records with your phone, or turn the game into a separate native release. Check the visible best and discoveries after opening it.
Float is another feature: where supported, it temporarily moves the live game into a small floating window connected to its original tab. Desktop installation is useful for returning later; Float is useful for arranging the current session. Prepare offline access separately if that is your reason for installing.