How do I save the game

You do not have to do anything to save the game, just make sure you are not in incognito mode and make sure your browser allows cookies and you are good to go. As long as you return within a 30day period and do not clear your browser cookies you will retain your save game.

It is recommended however that you backup your game by exporting it every so often by clicking the export button on the bottom left of the screen and saving the text somewhere.