Hello Prime Fellow!
In order to use Prime tools/content you will be asked regularly for Prime key and username, you will get this Key as soon as your membership gets upgraded, here's how you can find it:
It's as simple as that, just copy your Prime key and insert it where you asked to. Then validate your key with username and you are done!
[WARNING=Important Note!]Your Key contains sensitive data about your membership and it can be used to hijack your account or get some of your personal details.
[/WARNING]
[ERROR=Warning!]Sharing your Prime key will trigger a system alert and you will be risking a suspension of your account and IP block.[/ERROR]
. . . and have the ability to create lot of things.