After opening a project, you can launch a preview of it at any time using the “Play” button of the GDevelop toolbar:

From left to right: the Project Manager button, the Export button, the Play button and the Debug button.

You can also access more options by right clicking the “Play” button. The “Debug” button on the right allows you to open a Network Preview.

After you click the “Play” button to launch a preview, the game is opened and run in a separate window:

By clicking on the “Play” button, you can launch a preview of your game. By default, the preview will start with the scene that you're currently editing (or from the first scene if you've not opened any scene).

The preview will open in a separate window. Close the preview window to end it.

By default, the preview starts with the scene that you're currently editing. If you want to force GDevelop to start your game from another scene, open first this scene, then make a right click on the “Play” button and choose “Use this scene to start all previews”:

A flag will be added on the icon to remind you that the preview is always starting from the chosen scene, even if you're editing another one.

You can later remove this setting by using the same menu and uncheck the option:

By clicking the “Network preview (Preview over WiFi/LAN)” button, you can preview your game on mobile devices (or any other computer) connected on the same network as the editor:

After clicking the button, a window will appear showing the address the preview is being launched on:

You can now enter the given address in your smartphone browser (or your other computer browser). The preview will load:

The Debugger is a tool that can be used to inspect the content of your game (values of variables, existing instances and their properties…) and even do some real-time editing. The Profiler is a tool to inspect the performance of your game.

You can launch the debugger using this icon:

See this page to learn more about the Debugger and the Profiler usage.