In the top right corner there is a green button called 'View App'. Pressing this will lead you to your application, running in the cloud. If you ever want to migrate to another node, contact Support and they can help you with retaining your data. Hope this helps!
This is my page layout, only contain one button named ' Edit Button'
In your modeler, at the top of the screen make sure to click "Run" and not "Run locally". If it shows "Run locally" click the down arrow next to it and switch it to "Run". This will deploy your app to your free sandbox. Once its done deploying (takes a few minutes), you can click "view" and the modeler will open your browser to the correct link.