the problem is thinking of it as a chain. It's more of an overlay.
so for example, if the first part of your anim is 3 second the second 5 , the third is 2 and the last holds for 7sec.
you want the delays to be something like : 0s,3s,8s,10s... ( so essentially the the delay is the sum of the time of all the previous transitions)
hope that helps.