How much is Shar'iah law based on the Qu'ran?

From my understanding, Shar'iah law contradicts the Qu'ran in many ways, but when I did my research, I see that is based on the Qu'ran. So, what are Shar'iah's origins? Can you give me examples of Shar'iah and the Qu'ran's similarities and differences? Thank you.