How do I open a form or template I create?

Sorry, but I'm not sure I understand your question. Are you asking how to create a form or template via myforms page? If so, please check the links below.

https://www.jotform.com/help/2-How-to-Create-Your-First-Web-Form

https://www.jotform.com/help/106-How-to-Use-Form-Templates 

If you are asking about how to view or edit the form, just click on the form and you should see an "Edit form" button like in my image below.