It must be cut with a power saw and a masonry-cutting blade. It really cuts most readily. In the absence of a power saw, you may use pressure treated lumber, certified for ground contact. The little drawing, below, shows the side earth support only on the right side, looking into the steps. A handrail on one side of the steps is a useful addition.
Galvanized pipe is another possibility.
The only caution is to securely anchor the uprights in concrete. Holes some eight inches in diameter and a good eight inches deep should be dug for the supports. Fast setting post support concrete should be used. The railing must be supported while the concrete is added and until it sets. A level is advisable to make sure that the vertical posts are reasonably vertical.