Referral process at JPMC

Fellow Engineers working at JPMC,

What exactly is the referral process at JPMC ? A friend of mine who works at JPMC said he will just need phone and email to add a referral to me and I'll have to apply for the role I want by clicking on the Careers Site link that comes in the email.

Another friend of friend who also works at JPMC said once you are referred, you get an email saying you are referred by someone at the company. And that's it. No need to apply or anything.

Quite confused honestly. What really is the process here ? Am I supposed to do anything post referral ?