Which of the 4 ram slots do i put my 2 sticks in?

Again, read the manual. I have two Asus based builds here, one says use the colored slots, one says use the black. You want to use the slots that the manual says are correct for your specific model number. There is no universal answer.

http://dlcdnet.asus.com/pub/ASUS/mb/LGA1151/Z170-A/E10611_Z170-A_UM_V2_WEB.pdf

Look at the picture on page 1-8 and 1-9 where it says to install them an A2 and B2 not A1 and B1

These are the lighter of the slots, 2nd and 4th from the CPU.