In Online Store, right after you create a trial account, your store is visible on the internet under:
If you are on your dashboard and you want to have a quick preview of your store, just click the icon next to your store name. You will be able to see how your store currently looks.
If you want to change your domain, learn how to do it here.
During the setup phase, you can hide the visibility of your store. Learn how to do it here.