How to put my div three and div four in the second row of flexbox container? [closed]

I am doing theodinproject project and i want my main div which is flex-container to contain all the elements there are but i want my div three and div four to get on the next row i mean below div one and div two. But i dont know how i can achieve this. I am sharing my code.

I tried adding flex-basis to third and fourth div but nothing happened.