Sir how can I believe in hadith as a muslim.. because my ALLAH gives us a QURAN which is totally complete ? Is Quran is incomplete without hadith if no.. so why we believe in hadith what I think...

Hadiths are used to understand Quran better.

Quran, in itself, is a complete book.

In many cases, Quran shows us what to do and Hadiths shows us how to do.

Hence, To understand Quran better, Hadiths are must