Soundtoys licenses are managed on the iLok platform. Soundtoys licenses that you purchase or redeem are deposited into the iLok account you have listed in your Soundtoys account, and can then be activated to your iLok USB key and/or computer.* You can find full license activation instructions here. You can create an iLok account for free here.
* Computer-based activations require version 5 Soundtoys licenses.