Go to https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

Download the last release of putty :

Start install of putty :

In the start menu you have multiple new applications under PuTTY folder :

First step is tho genereate the SSH key. For this run the PuTTYgen

Click on Generate button

You need to move the mouse over the window

When completed you will get a new key

Before saving the key uptate the fields

In key comment put you email address

And enter a passphrase

Save the public key on you computer

Save your private key   Keep this file in a safe location ! And be sure to have a backup ! There is no way to recover the private key !

Now you ca provide the public key :   Just do a copy paste of this field