If you've already used the machine, you already have all the information you need to connect to the Virtual Machine via SSH. If you created the VM using the Quick Create option in the management portal, you created a password-based VM - easy.
If you cannot connect using the same ssh
command you used before, then perhaps the machine is hung or went down.
In the portal, find the VM, select it, and use the Restart option to reset it. Try connecting again to the machine in a few minutes.