Add a "Where do i find styles" section to the contribution guide (#127)

* Add information about source-code fonts

* Fixed a few formulations

* Updated a link

docs/source/docs_dev/contribution_guide.md

@@ -3,7 +3,7 @@
 Contributions from the community drive `tueplots`.
 Are you thinking about contributing to `tueplots`?
 If yes, that's fantastic!
-To make it as easy as possible for you, follow the steps below.
+To make it as easy as possible, follow the steps below.
 
 
 
@@ -14,18 +14,42 @@ Most obviously, new versions of existing style files (e.g., `tueplots` has `icml
 new venues are also interesting (e.g., `tueplots` has ICML's style files, CVPR is also in scope).
 For anything else, create an issue, and we will have a look together!
 
+## Where do I find the style files?
+
+A good source for the concrete values of, e.g., the figure sizes, are the conference's/journal's instructions for the authors.
+Some values are easy to find; for others, you have to dig deeper.
+The figure size and font size are usually mentioned fairly prominently.
+When implementing the font size in Tueplots, use the Figure captions as a reference, not the main text.
+
+The correct font implementation can sometimes be tricky because most templates use 'Times'; however, there are different ways of achieving a "Times"-like font.
+One often has to look at the source code for the Latex style file to find the correct font.
+Look out for the following information:
+
+* If the document uses `\includepackage{times}`, then the template uses the 'Times' font. Use the same font configuration as ICLR-2023.
+* If the document uses `\includepackage{ptm}`, the template also uses the 'Times' font but with a different package. Tueplots attempts to mirror this choice as closely as possible (by including the same package as the Latex template) even if it means including an obsolete package ([the 'times' package is obsolete](https://ctan.org/pkg/times)) .
+* If the document includes no font-related package, it likely uses Computer Modern. Copy the configuration from JMLR-2001.
+
+**Note 1:**
+The `times` vs `ptm` usage in Tueplots has been clarified by [pull request #125](https://github.com/pnkraemer/tueplots/pull/125) and does not affect version `v0.0.12` or older.
+
+**Note 2:**
+[Times and Times New Roman are different fonts](https://creativepro.com/times-roman-vs-times-new-roman/).
+And since there is no native Times New Roman implementation in Latex unless one uses XeLatex ([see this link](https://tex.stackexchange.com/questions/153168/how-to-set-document-font-to-times-new-roman-by-command)), be sceptical if a template claims to use Times New Roman but provides a Latex style file.
+Always consult the style file's source code to identify the correct font.
+
+
 
 ## How do I make a pull request on GitHub?
 Making a pull request on GitHub can seem complicated if one is not used to doing that, but luckily, there are many guides:
 
 - [This](https://docs.github.com/en/get-started/quickstart/contributing-to-projects) is GitHub's guide for contributing to open-source projects, including explanations of the terms "cloning" or "forking".
 - [Here](https://docs.github.com/en/get-started/using-git) is information about working with `git`.
 - And [this is how](https://www.freecodecamp.org/news/how-to-write-better-git-commit-messages/)  we can all write better commit messages.
-- Using a virtual environment is generally a good idea when working with Python projects (such as `tueplots`). [This guide](https://realpython.com/python-virtual-environments-a-primer/) describes the basics. Be aware that if you place your environment inside the `tueplots` root folder, `tueplots`' auto-formatting might attempt to format the source code inside the environment, which is unnecessary.
+- A virtual environment is generally a good idea when working with Python projects (such as `tueplots`). [This guide](https://realpython.com/python-virtual-environments-a-primer/) describes the basics. Be aware that if you place your environment inside the `tueplots` root folder, `tueplots`' auto-formatting might attempt to format the source code inside the environment, which is unnecessary.
 
 
 A small project like `tueplots` might be the perfect place to start contributing to open-source projects.
-If you would like to help but do not know where to start, reach out!
+If you want to contribute but need help knowing where to start, reach out!
 
 ## Where do I put my code?
 
@@ -36,14 +60,14 @@ Check out the [continuous-integration](https://tueplots.readthedocs.io/en/latest
 Then, roughly follow these steps:
 
 1. If you like to add a new style file, it would be ideal if you contributed four things: bundles, figsizes, fontsizes, and fonts. The remaining modules (axes, cycler, markers) are usually unimportant for adding a new style file.
-2. Start by adding test cases to `tests/test_rc_params_cases/test_{fontsizes,figsizes,fonts,bundles}.py`. Take the existing cases as a reference. The next time you run `tox`, the tests will fail (which is expected).
-3. Fix the failing tests by adding the corresponding functions to `tueplots/{fontsizes, figsizes, fonts, bundles}.py`. A good source for the concrete values of, e.g., the figsizes, are the author instructions that each conference/journal provides. Some values are easy to find; for others, you have to dig deeper. If you cannot find something, contribute what you can! Now, all tests should pass again.
+2. Add test cases to `tests/test_rc_params_cases/test_{fontsizes,figsizes,fonts,bundles}.py`. Take the existing cases as a reference. The next time you run `tox`, the tests will fail (which is expected).
+3. Fix the failing tests by adding the corresponding functions to `tueplots/{fontsizes, figsizes, fonts, bundles}.py`. If you cannot find something, contribute what you can! Now, all tests should pass again.
 4. A lot of this will be copying/pasting existing code. Remember to update the docstrings of the pasted code.
 5. If you like, add a corresponding cell to one of the example notebooks. This step is optional, but sometimes it helps to see the configuration "in action".
 
 
 Commit the results and open a pull request.
-In the pull request's description, mention what you have contributed and where one can find the information. For example, write something like this:
+In the pull request's description, mention what it contributes and where to find the information. For example, write something like this:
 
 
 
@@ -54,6 +78,6 @@ In the pull request's description, mention what you have contributed and where o
     Most values are the same as in previous years; see <link-to-call-for-papers> for reference.
 
 
-Once this is done, we will process the pull request as quickly as we can.
+Once this is done, we will try to process the pull request as quickly as possible.
 
 Thank you for contributing to tueplots!