How do you trim this shrub into a ball?
Certified GKH Gardening Expert
These are real easy to shape, but you have to be careful not to cut all the foliage off the branches, and it's probably best done over a couple of years/seasons rather than trying to shape it all at once. Cut away all the lower branches close to the stem, standing back and looking as you go. You can't replace the branches once you remove them, so go easy until you get the feel of the size/look you want. After the stem is the right height, start at the bottom branch and shorten to the width of the ball shape you want, all around the shrub. Work your way up the higher branches until you are satisfied with the shape and height. Keep in mind that you could end up with bare patches within the shape of the ball, as you might have to remove a heavy foliaged branch, but within a couple of years and the right pruning, this will fill in. It won't be shaped and tight growing for a couple of years unless you are reshaping a previously shaped shrub.
In the event that you're looking for topiary instructions, this article should help: https://www.gardeningknowhow.com/garden-how-to/projects/how-to-make-your-own-topiary.htm