Update on CONTRIBUTING.md (#388)

# MetaCall documentation (CONTRIBUTING.md)
Edit on MetaCall documentation to help newbies start contributing faster.

Fixes #387

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
- [ ] This change requires a documentation update
- [x] Documentation update

# Checklist:

- [x] I have performed a self-review of my own code.
- [x] I have commented my code, particularly in hard-to-understand areas.
- [x] I have made corresponding changes to the documentation.
- [x] My changes generate no new warnings.
- [x] I have added tests/screenshots (if any) that prove my fix is effective or that my feature works.
- [x] I have tested the tests implicated (if any) by my own code and they pass (`make test` or `ctest -VV -R <test-name>`).
- [x] If my change is significant or breaking, I have passed all tests with `./docker-compose.sh test &> output` and attached the output.
- [x] I have tested my code with `OPTION_BUILD_SANITIZER` or `./docker-compose.sh test-sanitizer &> output` and `OPTION_TEST_MEMORYCHECK`.
- [x] I have tested my code with `OPTION_BUILD_THREAD_SANITIZER` or `./docker-compose.sh test-thread-sanitizer &> output`.
- [x] I have tested with `Helgrind` in case my code works with threading.
- [x] I have run `make clang-format` in order to format my code and my code follows the style guidelines.

.github/CONTRIBUTING.md

@@ -1,7 +1,17 @@
 # Contributing
 
 When contributing to this repository, please first discuss the change you wish to make via issue,
-email, or any other method with the owners of this repository before making a change. 
+email, or any other method with the owners of this repository before making a change. Here is an examplary process you can follow to create an issue on MetaCall:
+
+1. Identify a problem or a possible addition to Metacall codebase/operation<br>
+for instance: ```pre-commit-clang-format not working on windows...```
+2. Then go to the necessary MetaCall gitHub repository and click on the "Issues" tab at the top of the page. Indicate your issue's interest by tagging it as a bug report, custom issue, documentation, feature, or discussion. <br>
+in this case: ```metacall/core```
+3. Type in a title and description for your issue. Be as detailed as possible, including any error messages or steps to reproduce the issue. Image example: <br>
+![issue image](https://user-images.githubusercontent.com/93955843/220493308-0ce3f101-6957-43fb-96d1-7a730ccf304c.PNG)
+
+4. You can assign the issue to yourself, add labels or a milestone to it, and attach files if necessary.
+5. Submit the newly created issue and start working on a solution by creating a fork of the repository. <br>(<a href="https://github.com/metacall/core/issues/370">Here</a> to issue used for explanation)
 
 Please note we have a [Code of Conduct](/.github/CODE_OF_CONDUCT.md), please follow it in all your interactions with the project.