Hi, and thank you for your interest!
Openbmap is being translated using Weblate, a web tool designed to ease translating for both developers and translators.
Translation project for Openbmap into Chinese (Traditional) currently contains 221 strings for translation and is 8.5% complete.
If you would like to contribute to translation of Openbmap, you need to register on this server.
Once you have activated your account just proceed to the translation section.