Pippi, hydrangeas are a piece of cake to root.
Take the new wood, where the green wood meets the brown (old wood). Dip into rooting hormone, either powder or liquid, make a hole with a pencil in your rooting/potting medium, insert cutting, water in to close the dirt/potting soil around the cutting. Keep moist.
If your leaves on the cuttings are large trim them back by half.
Here is a pic of hydrangeas in a "rooting box" (plastic tote).
Shoe
