AsteroidOS translations are managed through Weblate, a Free/Open Source web translation platform. To be able to use it, you will have to register an account, although you can also log in through a few popular third-party services. The rest of this page assumes you have an account.
Updating translations for an existing language is quite simple. Simply go to the AsteroidOS Weblate page, choose the project and language you want to translate and start translating.
If the language you want to translate to is not supported yet, please join #asteroid on Freenode to tell us which language you’d like to see supported and we’ll set it up for you.