For mapping the requirement with test cases we do: 

1. In requirements tab select coverage view
2. Select requirement by clicking on parent/child or grandchild
3. On right hand side (In coverage view WINDOW) another window will appear. It has two tabs:

-Tests coverage
-Details

Test coverage tab will be selected by DEFAULT or you click on it.

4. Click on select tests button a new window will appear on right hand side and you will see a list of all tests. You cans elect any test CASE you want to map with your requirements.

For mapping the requirement with test cases we do: 

1. In requirements tab select coverage view
2. Select requirement by clicking on parent/child or grandchild
3. On right hand side (In coverage view window) another window will appear. It has two tabs:

-Tests coverage
-Details

Test coverage tab will be selected by default or you click on it.

4. Click on select tests button a new window will appear on right hand side and you will see a list of all tests. You cans elect any test case you want to map with your requirements.