If we have setup a SSH session for you, we would have shared the private and public key in your Hudu profile for that specific instance as well as the host name.
You will need the id_rsa.ppk file which will be included in the specific Knowledge Base article for that instance in your Hudu profile.
Once you have saved that in a safe location (be very protective of this file as well as the id_rsa.txt file!!!), go ahead and start PuTTY.

Fill in the Host Name or IP address (if in doubt, use the IP address) for this session and then change the Port to the one recorded in the specific KB article for this instance in your Hudu profile.
Give this PuTTY session a Name and then click the Save button to save the edits so far.
On the left hand side, click on the + sign beside SSH and then click on the + sign beside Auth.

Select Credentials.
In the Private key file for authentication option, click the Browse button and locate the id_rsa.ppk file that you saved from the Hudu KB article for this instance.
Scroll back up to the top of this menu and click Session. Make sure you save this again so that the Private Key location and file are saved as part of this PuTTY instance.
You can now click the Open button in PuTTY to start your session.
If this is the first time you have accessed this instance, you will be asked to accept the fingerprint - go ahead and do so to get to your SSH session.
When you get to the login screen, you will use the user account setup for you (NOT the root user!!). Go ahead and type in the user name.
The password is NOT the password for that account but is the KeyPhrase for the Private Key that you installed in this PuTTY session - this too you will find in the Password section for this specific instance in your Hudu profile.
You are now connected!. Remember, you will need to use the 'sudo' command to accomplish any tasks in order to have the proper permissions to do so. The first time you run a 'sudo' command, you will be asked for your password - this will now be the proper password for the user you are using which you will also find in the Password section of your Hudu profile.