Hi, and thank you for your interest!
AppStream is being translated using Weblate, a web tool designed to ease translating for both developers and translators.
Translation project for AppStream into Serbian (latin) currently contains 186 strings for translation and is 15.0% complete.
If you would like to contribute to translation of AppStream, you need to register on this server.
Once you have activated your account just proceed to the translation section.