Update CONTRIBUTING.md

Author: giangiac

CONTRIBUTING.md

@@ -2,11 +2,22 @@
 
 Thanks for your interest in the project! 
 
-Any contribution, project participation and pull request from developers of all skill levels is welcome. Please follow this process:
+Any contribution, project participation and pull request from developers are welcome. Please follow this process:
 1. create a new branch (out of the current master branch and with a descriptive name)
 2. implement your changes
 3. start a pull-request (merge into master branch)
 
+1. Clone this repository or fork it. Create a new branch and add your modifications.
+2. Remember to add unit tests to verify the desired behavior of the new features or methods.
+3. When the first version of the code is ready, create a pull-request to the **development** branch of `iqusoft/intel-qs`.
+4. Edits may be required to resolve conflicts since it is possible that the repository has changed while you worked on your new contribution.
+Please resolve the merge conflicts.
+5. Verify that all unit tests, and not only the one added in the contribution, run correctly.
+6. The IQS team will help with the revision of the pull-request.
+
+To facilitate the review consider starting with small contributions (a couple files and ~100 lines).  
+For contributions that require substantial changes or changes in many files, please contact the IQS team to discuss the most effective strategy.
+
 Creating your pull request from a fork? We suggest allowing edits from maintainers. Then, anyone with Write access to the upstream repository will be able to add commits to your branch. This can make the review process easier for maintainers since they can make a small change themselves instead of asking you to make the change.
 
 If you would like to contribute to IQS, please visit our wiki page [https://github.com/iqusoft/intel-qs/wiki/Contribute](https://github.com/iqusoft/intel-qs/wiki/Contribute).