Please tell me What are the duties of a Automation Tester in real time

Anyone please tell me the daily life of a automation tester which includes

1)How he will get a work,i mean who will assign work to him

2)If defect raises how he reports and the procedure of closing a defect

3)What type of test he will do,will he do complete end to end test or unit or integration

4)Mainly,How a tester will convert functionalities into test cases and also how he will estimate a work

Please tell me its very important to me to know Thank you in advance...**