Contributing can take many forms, and it's not just for developers.
Many of the workbench features were added because the developers thought they might be useful to others or themselves.
Do you think a feature is missing? Is some step in the workflow hard to accomplish? Do you want to work on a new/missing STEMFIE component? Let us know.
This may be one of the most undervalued type of contribution. FreeCAD and the STEMFIE Workbench aren't only for people speaking English. Translating different languages requires the contributions of native speakers worldwide.
The STEMFIE Workbench, like FreeCAD itself, uses the CrowdIn platform https://crowdin.com/project/freecad-addons for management of translations. Create an account and you'll be able to start contributing right away. In addition to providing translations, you can also proof read the translations already contributed. Do a little or a lot. Even small incremental gains are valuable.
Of course, you can do translation locally on your machine, to know more about the translation process take a look on the README file on the translations directory.
Some beam icons may need to be improved to be easier to identify.
Here are FreeCAD guidelines for icons: https://wiki.freecad.org/Artwork_Guidelines
What can be done to improve your experience? It is easy to overlook an accessibility issue when you're not personally affected but it's often easy to accommodate once the issue is known.
See a bug? Open an issue on GitHub: https://github.com/bilbaomakers/StemfieWB/issues
You can test latest changes on: https://github.com/bilbaomakers/StemfieWB/tree/develop
If you have QA experience consider writing test cases.
Feel like adding a new feature/part? Open a ticket to use as a basis for discussion.
Describe your idea. Discuss with the other developers and start coding!