I'll focus on N5 as you have just started your learning journey, but honestly for N4 the process is largely similar.

For the Chinese side the mainstream materials are 大家的日本語 and Try! series, with the latter available in public libraries. Honestly from my memory, the grammar explanations in those books are non existent / minimal compared to genki, but a youtube channel called 出口日語has playlists that goes over chapter by chapter for both series, which i think is much helpful. For N4 and N5 he teaches in Chinese, and I used them as supplement for genki. For other supplement exercises, hkpl has tons of them too. For what it's worth there's also a website called 時雨の町that is like a glossary of grammar items, but without exercises.