spark plugs location

I already took out the top engine cover on my 07 sienna 3.5 but I dont see any spark plugs not even the wires. Could someone pls. tell me which ones are they? or are they underneath something I have to unbolt before I can see them? Haynes manual doesn't show where they're located. It only say that the other 3 at the back is located underneath the intake manifold cover. But I cant even see the 3 at the front. Thanks for your help.