Welcome to our Community.
Can I know where did you purchase the license key from? And is it for the F-Secure Key?
Got F-secure safe with phone I bought from ideal world shopping chanel covers three devices for one year.
EDIT : Move to the correct board since you're using SAFE.
I think you'll need to create an account on the F-Secure SAFE Portal, then you should be able to use your subscription key and install onto your devices from there.