When you need to put in the licence key, hit the drop down button next to the prime licence code that is shown when you first start studio one after installation.
The prime key shows as it's the first one attached to your account. The drop down should show you your artist licence key if both keys (prime and artist) are tied to the same account. Select the Artist key and click O.K.
Once you have done that, you will need to install any missing content between versions. Once you have the start page up, go to the top menu and select installation/activation and install missing content from there.
Hope that helps.
