We can map the requirements with test cases in QC:
1. In the requirements tab SELECT COVERAGE view.
2. Select requirement by clicking on parent/child or grandchild.
3. On RIGHT hand side another window will appear. It has TWO tabs:
(a) Tests coverage
(b) 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 can select any test case you want to map with your requirements.

 We can map the requirements with test cases in QC:
1. In the requirements tab select coverage view.
2. Select requirement by clicking on parent/child or grandchild.
3. On right hand side another window will appear. It has two tabs:
(a) Tests coverage
(b) 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 can select any test case you want to map with your requirements.