To understand these Agile process terms let’s take an example

Epics

Epics declare initiatives important to the organization’s success. Epics may take several teams and several sprints to accomplish, but they are not without an end. Epics have a clearly defined goal. Once attained the Epic is closed. The number of Epics in progress should be manageable, to keep your organization focused. Epics are broken down into Features. Many organizations introduce a level above Epics called Initiatives, Initiatives break down into Epics.

Features

Features define new functionality required to realize an Epic’s goal. Features are the release unit, that is, they represent what is released to the customer. Your published release notes can be built based on the list of Features recently completed. Features can take multiple sprints to complete but should be sized to ensure a consistent flow of value to the customer. Features are broken down into stories.

Stories

Stories define incremental value the team must deliver to create a Feature. The team breaks the Feature down into incremental pieces. A single completed story may not provide meaningful value to the customer. However, a completed story represents production-quality software. Stories are the team’s work unit. The team defines the stories required to complete a Feature. Stories optionally breakdown into Tasks

Tasks

Tasks define the work required to complete a work item.

Example

If you design a school Management project 

States can be New, Active, Resolved, Closed

Epic 

• Attendance Register
• Student Registration
• Library Management
• Finance Management

Features

Time Table

Books Catalog

Student Signup

Notice board

Fee Structure

User Stories

• Define the login to portal process
• When a user wants to see the results on the web portal
• As an admin, modify student’s detail
• As a student can see the marks of the academic year.

Tasks

As a user, I want to view a public landing page with static information.

As a user, I want to list all the students class-wise.

As a user, I want to see the results of all the students subject-wise

Issues

• The user is not able to log in
• Networking is not established between Web servers and DB servers
• Waiting for test results

Bugs

• Application is throwing an exception on the login page
• Reports are not showing accurate results.

Test Cases

• Verify whether existing users are able to login with their credentials or not.
• Verify school logo has appeared on all the web pages.