If you want to contribute with translations for your local lenguage o other language, just create an Transifex.com account and request to join for the team translation
Me initially because a need theses resources updated in Spanish and eventually when are new changes from the Sphinx files from the Github repository GitHub - plone/training: Plone Trainings
If you are refer to Who is pulling the changes into the training resources into Github repository? well at the moment me via "Pull request" as the Spanish Translation Team Leader.
When I complete the translation I pull fron Transifex the po files into the Github repository ans rebuild the Plone training resources with my translations using a lite changes into Makefile like the following:
.PHONY: html_es
html_es: bin/sphinx-build
$(SPHINXBUILD) -D language='es' -D html_search_language='es' -D project='Entrenamiento Plone 5' -D copyright='''El texto y las ilustraciones en este sitio web son licenciadas por la Plone Foundation bajo la licencia Creative Commons Attribution 4.0 International''' -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html/es
@echo
@echo "Build finished. The Spanish HTML pages are in $(BUILDDIR)/html/es."
Note: Just replace es for your locale code and translate the Sphinx variables values in your language.
Then I do the review the translations applied directally into the resources, fix any changes locally and push these changes to Transifex.com using tx command (Transifex client) and then mark this new improvements as Reviewed.
To finish the integration of the new translations into repo github just do a commit and pull request.
The workflow between GitHub and Transifex used is the following:
Maybe @pbauer as a Plone Training maintainer, he can share you opinion about what the right workflow to maintain integrate the last changes from Sphinx resources files into Transifex and vice versa.