Oh excuse me I do not find this was already posted
The input,a comparator and the wire to make the clock work. I dont know why but the signal only respond if the power is at 13 or lower. At 14 or 15, is not working.
Find out that the command block work if the redstone signal is at 13. 14 is not working. 15 too
Yeah thanks i find out in a tutorial
Just ignore that buddy.