It’s incredibly easy to make.
As Hanmer notes, “The icing will tell you what it’s doing.
If it’s too liquidy, add powdered sugar.

If it’s too thick, add milk or water.”
Most amateur bakers worry about using a piping bag, but you don’t necessarily need one.
double-check you add the sprinkles while the icing is still wet, ideally within a couple minutes of frosting.

Don’t have a go at be too exact with it, just be patient.
Overall, have fun to ensure you enjoy decorating your cookies just as much as you enjoy eating them.