If you closed PuTTY, then run it
Double click on the name of your session under “Saved Sessions”
Type your username when prompted
If this is the first time you have logged in, you will also be prompted for your “old password”. This is separate from your passphrase, and should have been sent to you. You then will change your system password. Keep track of this password, because under most circumstances the only time you will be prompted for this is when it is time to change it. You will need to change your password every 35 days or you will be locked out when you try to access the server next. You will have to use PuTTY to change your password. You will not be able to use WinSCP to change passwords.