Timer Problems

I have just started to use 2 flowering tents, using 12/12 with the lights, but what one on when the other is off.
with the timer I can get both on or off at the same time but don't want to do this as the wattage is too big.
how do I set my timer to get one coming on as the other goes off etc

buy another timer

Apparently this timer will do it but I don't know how to set it!

list co and model#