There are many ways, however, in the interest of speed, a function node containing ...
msg.payload = [ { RANDOM_NUM: msg.payload.values[0].v } ]
return msg
... will work.
Also possible with a change node, a template node and others.
In future, please post sample data instead of a screenshot (we can use sample data in a working example without having to type stuff out)
Canned tips for newcomer
Getting the EXACT path (like msg.payload.values[0].v) and copying usable data
There’s a great page in the docs (Working with messages : Node-RED) that will explain how to use the debug panel to find the right path to any data item.
Pay particular attention to the part about the buttons that appear under your mouse pointer when you over hover a debug message property in the sidebar.
How to post Code properly
In order to make code readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)
```
code goes here
```
You can edit and correct your post by clicking the pencil 
icon.
See this post for more details - How to share code or flow json
Recommended essential playlist to get up to speed quickly
I recommend watching this playlist: Node-RED Essentials. The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot more in about 1 hour. A small investment for a lot of gain.
