The larger "Number of bits in a generated key", the more different to be cracked. Please use at least 2048. 4096 is recommended.
Click "Generate", move the mouse cursor over the blank area until you see your key.
Copy the text inside the "Key" text box. This is your "public key", which starts with "ssh-rsa". Make sure you copy all the text.
You can enter "key comment" or "key passphrase". If "key passphrase" is specified, using the key requires entering password. Click "Save private key" to save a ".ppk" format key. NEVER give your private key to others!
To use your key, launch Pageant. It will load and show in the notification area. Double-click to open its main window.
Choose your private key.
The private key is loaded and ready to be used.
Public key is for others. Private key is for yourself. DON'T MIX THEM UP!