What can be done to this matrix to make it more obvious to end user to click on number to see list of items in it, when a user will click on the box, if there any number shown on it e.g. starting from "1" then it will show a list of items on the right side,

![enter image description here](https://i.stack.imgur.com/t6xcG.png)

I am going to make it a like a graph.