JIRA how to use epics code example

Example: what is epic in jira

Epic is basically biggest user stories.
It is almost everything about one project.

Example--
AS CUSTOMER I SHOULD BE ABLE TO BUY FROM AMAZON,
SO I DON'T HAVE TO GO TO LOCAL STORES.

Basically this epic example is everything about amazon.com
It includes like login, logout,
search, basket, shipping etc. functionalities