Add kale to blender. I like to add my greens first thing.
Add pineapple and banana. The fruit goes in next, it doesn't matter which order you put them in.
Add liquid. The liquid will seep in the areas around the fruit and greens, so it will get to the blades.
Blend until smooth. Turn on that blender and let it do its thing!
Notes
This is my preferred order for adding ingredients. If yours has trouble blending, try adding the greens and liquid first and blending, then add the rest of the ingredients.