Explain in detail about header section

Writing-Test-Plan-Items.md

@@ -1,16 +1,53 @@
 ## Test Plan Items
 
-A test plan item should specify its complexity from 1 till 5 and should have the platforms in which it has to be tested against. You can pre-assign them to a user you would like to test by adding his/her user id next to platform. If there are more than one authors for it, all the authors should be specified. Test plan item description should contain all these details. Following are the examples:
+Test Plan Items (TPIs) are the issues created with label `testplan-item` for testing the features during the endgame. There is a tool that parses all these TPIs and generates user assignments. Endgame master uses this tool to assign these TPIs to others for testing.
 
-### Platforms
+A TPI should contain **Header** and **Body** sections which are separated by `---` (line). Header section shall contain the meta information about the TPI that is used by the tool for generating TPI assignments. Body section shall include testing details for the user to test.
 
-- macOS
-- windows
-- linux
-- wsl
-- ssh
-- dev container
-- anyOS
+### Header Section
+
+Header section should be separated using `---` (line) 
+
+```markdown
+
+<!-- Header Section. -->
+
+---
+
+<!-- Body Section. -->
+
+```
+
+It shall contain following:
+
+- References to issues being tested
+
+```
+Refs: <!-- Refer to the issue that this test plan item is testing. -->
+```
+
+- Platform assignments mentioning on which platforms this TPI shall be tested. You can pre-assign them to a user you would like to test by adding the user id next to platform. Refer #examples.
+  - macOS
+  - windows
+  - linux
+  - wsl
+  - ssh
+  - dev container
+  - anyOS
+
+- Complexity of the test plan item which should be between 1 till 5.
+
+```
+Complexity: 4
+```
+
+- If there are more than one authors for it, all the authors should be specified so that they will not be assigned for testing
+
+```
+Authors: @user1, @user2
+```
+
+## Examples
 
 ### Example 1 (Platforms)