Save and Run buttons
By default, every time you save your project runs and automatically updates the preview. You can save and run your project by clicking the "Save All + Run" button in the header.
You can also use the keyboard shortcut to save your current file (Command + S for Mac, CTRL + S for PC).
If you don't want to update your project preview on on each save, you can enable a separate Run button in your Project Settings. Set the radio button under "Preview Updating" to "I want to use a run button to update".
After you save that setting, a "Run" button and "Save All" button will appear in the header.