The biggest mistake new bakers make is scoring too deep and too wide. It is not necessary to stab the bread like you are avenging some long dead family member. Instead, a simply slash will do.
I own a bakers lame, pronounced “Lamb”, just a slightly curved blade with a plastic handle. They cost a few bucks online but a sharp knife will work just fine.
You want to score your bread after the dough has risen and is just about to go into the oven. You can slash in any shape you want.
A hash (#) is a popular design but literally any cut will work. Experiment and see what looks pleasing to your eye.
When you cut slice at a slight angle and go just under the surface, not too deep. As I wrote about in my previous post, you are creating an area of weakness that the expanding air will escape. The cut will open up, think like a sliced baked potato, the edges will become slightly black and will add a depth of taste, texture and visual uniqueness to your boule.