Create a Transifex resource for rdsys i18n

I'm getting started with i18n for rdsys (see tpo/anti-censorship/rdsys#11 (closed)). I would like to use Transifex and need help with creating a new resource (at least I think that's what I need). In the beginning, I would like to experiment in Tor Project Sandbox because I have no idea how i18n works and I'm likely to mess things up.