Transifex.net has its own comprehensive documentation for transifex-client at http://help.transifex.net/user-guide/client/index.html. You can also post questions to the Docs Project mailing list or ask in the #fedora-docs IRC channel if you get stuck. The L10N Guide has lots of useful information on using Transifex from a translator's perspective: https://fedoraproject.org/wiki/L10N/Guide.