Jetstream is not directly accessible via XSEDE's Single Sign-On Login Hub.
Users are required to have XSEDE accounts. Newly created XSEDE accounts must be added to a Jetstream-specific allocation by the PI or Resource manager in order to access Jetstream.
Please note that your XSEDE Portal password is not used for logging into VMs. If you wish to use password authentication to ssh into a VM (not recommended!) you will need to set up a password (refer to Logging in with SSH for information)
Jetstream allows multiple methods for accessing and using your VM:
Web Desktop - Images with VNC/GUI/Desktop enabled will display under the LINKS items in the instance detailed view (found by clicking on the instance title). You may have to use your browser's refresh button to make it appear.
Simply click onto start a browser-based VNC implementation.
Some images support additional mechanisms for accessing your VM. Some of these additional access methods are noted in image specific documentation.