Hi, and thank you for your interest!
yast-base is being translated using Weblate, a web tool designed to ease translating for both developers and translators.
Translation project for yast-base into Croatian currently contains 953 strings for translation and is 57.2% complete.
If you would like to contribute to translation of yast-base, you need to register on this server.
Once you have activated your account just proceed to the translation section.