First of all sir, U must know whats Regression Testing is 
(RT): It is the testing done on a module when its modified.

Some times RT is done using Automation Tools.

RT is of 3 kinds :
Unit : Testing is done only on that part where the module 
is modified.

Regional : Testing is done on those parts inan application 
whereever the changes made in the module gets affected.the 
modified modeule is also tested.

Full : the whole application is tested.

Regression Testing is done on modified build to ensure the 
old functionalities still works fine with new changes.
 
Regression Testing is done usually With Automation Tool

Steps involved in Manual Testing Process:

1. After one cycle of testing is completed and bugs are 
fixed then u will get a modified build.

2. Start downloading the modified build

3. Perform Smoke and Sanity tests

4. Execute Those test cases which are of Resolve/Fixed and 
Resolve/Works for me. 

5.If time permits execute all test cases other wise Execute 
only High priority and Regression suit test cases.