This question is not well framed. There are two parts to your question - one is about designing a low-power flip-flop and another part is about using a layout tool. There are numerous papers about designing low-power flip-flops You can do an Internet search for "flip-flop with a dynamic latch (slave latch) for low power" to locate papers that may help you. Once you finalize your design, you can use the tool to transfer the design to a layout. Questions about the tool are best taken up with the online forum.