You can use PuTTY to establish an SSH connection using public key authentication as follows:
Select the desired project.
On the Website tab, click SFTP &SSH.
Next to Status, click Deactivated.
In the Password field, enter the desired password and repeat it.
Copy the public key.
Insert the public key in the Public key field.
In the Host name (or IP address) field, enter the IP address of your server.
In the menu on the left, under Category, expand the section Connection and click Data.
Type the user name in the Auto-login username field.
In the menu on the left, under Category expand the Connection and SSH sections and click Auth.
Next to the field Private key file for authentication: click Browse.
Select the Private key.
To establish the SSH connection, click Open.
A warning will appear when you log in for the first time. Because the SSH server was previously unknown, PuTTy does not have a stored key yet.
To allow the connection and save the key for future sessions, click Yes.
The SSH connection will be established.