The Online version is only good for 1 return. But you can use the same email address for 5 accounts. To do another return you have to set up a new account and new user name and pay any fees again. So if you have more than 1 return to do it might be better to buy the Desktop program. And Desktop has more features.
How to start another return in the Online version
Do you want to buy the Desktop program? You can buy it here, (or check in the stores for sales or Amazon,etc.)