Hello Damola, welcome to the Ranch.
In your question you are talking about a program, which is, I presume, a program that you got from a course you are following. Without seeing the original program, it's hard to help you with this. Also, please explain what you've tried yourself and where you are stuck - that way, we can help you get over the problem and you can learn.
If you don't know how
Java's
switch statement works, then take a look at this page in Oracle's Java Tutorials:
The switch Statement