On the right hand side of a case there is an area where you can 'Add Score.' This is highlighted in the image below.
The below image shows the Available Scores and these are set up under Scores & Goals in case settings. See this article for more information. All Scores have to be predefined so if they are not set up in case settings then they will not appear in this list.
For this example I have clicked on the 'How do you feel today?' score. It brings up the image below.
You enter your value by clicking on the blue box under Score. This then brings up the number tab where you set your score.
This then appears on the graph which you can see in the image below.
Once you close out of the Add Score screen it appears on the case like the image below.