Your counters should come immediately off of the double circle block similar to your last challenge. This one takes some repetition to get comfortable doing it at a rapid pace.
The handwork should be very fluid in this challenge. Time the blocks and strikes to move with the movement or rotation of your body. This is especially important on double strikes as there is no rotation to help generate power.
Learning how to engage the glutes in this kick is very important. Watch the hook kick basics – building the kick and a detailed education videos to develop the technique properly.