Before you start preheat the oven to around 400. Temperature isn't terribly important but you want it hot enough to crisp everything up pretty quick.
Now what you want to do is chop up your kale, just a rough chop. I would make them pretty small, easier to deal with, but it's really up to you. You want it small enough to spread evenly on your baking sheet without any overlapping but big enough that you don't get any tiny pieces that will just burn away.
Keep an eye on these, they can burn pretty easily as soon as you stop paying attention. After about 10 minutes I would open the oven and give them a good shake, maybe even a toss. If I find that they're not crisping like I want them to I will turn the broiler on for a minute or two but you definitely don't want to walk away from that! When you're done you'll have amazingly crispy and delicious kale chips that will melt in your mouth and disappear in seconds!
Enjoy!