drawing flipflop after statement table and kmap simplification
your table it's good. this is schemat your counter. step 1 is for flip A.

Current state depends on previous states of the entire system. DA current state set based on the expression CD '+ A'BC' + AB'D. The variables A, B, C and D are inputs to determine the output latch. Change in output will come in time clock for clock input. Similarly, the subsequent expressions. We install the system as shown.

DA whether the output of flip-flop A depends on the input expression which is the sum of CD '+ A'BC' + AB'D. As the condition counting starts from 1111 should use the counter and set it to 0 (PRE '= 0), the state active low. Compare STEP 1. The drawing shows exactly what I wrote. Written expressions are different for flip-flop A. Similarly connects to the next flip-flops. :)