Any UVI product registered after March 25, 2014 includes a license with 3 activations. This means you can activate the license on up to 3 locations simultaneously (any combination of computers and iLok dongles).
Please have a look at the following articles for detailed instructions on how to activate your license and manage your activations:
Any UVI product registered before March 25, 2014 was delivered with a single-activation license. However, you can purchase additional activations for a small fee, see the article Can I Purchase Additional Activations for my License?.
To check the number of activations on your license and how many remain available, please refer to the article How many activations do I have?