Using multi-computer license (3 PC) for Norton Internet Security

Hi ...

 

I purchased a multi-computer license (3 PC) for Norton Internet Security (17.7.0.12).  I have used 1 key and have 2 remaining activations. I have Norton Antivirus (16.8.0.41) installed on another computer and the subscription has expired.  I would like to  update this computer to Norton Internet Security using one of the remaining activations.  How do I do this - thanks

 

Chris