Hi! The pack of 5 licenses lets up to 5 developers use Prodigy at the same time. How you do that is really up to you and your requirements – you can run Prodigy on a local machine on localhost, run multiple instances on differen hosts/ports or deploy it in the cloud. The licenses apply to the people using Prodigy, not the machines (since that'd be really impractical).
In a typical workflow, you'd probably have the developers running Prodigy on their local machines during development and to quickly try out ideas and create prototypes. Once you're ready to collect more annotations, you could then run one or more instances in the cloud or on your local network and expose it to your annotators.