At which level the tester starts writing the test case document?

Hello ,

I want to know that at which level the tester starts writing the test case document in Manual or Automation Testing.

After writing the test cases Testing is performed or what ??
Pls let me know the procedure with the view point of Software Tester...
I m beginner..

Thanxs

Hi,
Once SRS gets created ,tester starts creating scenarios based on it,ant then starts writting testcases.Once tester will finish writting testcases, tester will perform review on it to map requirments with testcases...and then module /submodule /system will get from developers team testers will start executing those testcases.