in your picture , in the left section under the asio you have selected is the scarlet driver ,if you click on to that then you can adjust the latency in there , everyone will suggest and different setting but 128 is normally quite good for low latency and to stop the pops and click .
You need to have them both connected to the computer you don’t connect impulse to the soundcard
If you load the novation driver ,in the device setup menu at the top left corner there is a plus sign and if click on that and add novation then that should select you controller keyboard.
hope that makes sense to you 