I can easily answer that question for you, @bryansailer
. When rooting plumeria, the rule of thumb is that leaf-growth is a sign of root formation, so that's actually what you look for. That is certainly not always true. I have had many cuttings root before any leaf-growth. But in general, if you see leaves growing, the plant should be rooting. You know to keep the cutting(s) dry until roots/leaves have begun to grow, right?
By the way, it would be nice to know where you are, since conditions are so important when asking or answering questions. Just go to your "Profile" and update your Public Profile with your location. City and state are best but at least give your USDA zone.
Also, there is a wonderful "Plumeria" forum and you'll find lots of help there.