Hi @emilk
Welcome to the forum.
Let me recommend (via canned text) a few things that should put you in good stead. Once you've covered these, come back and evaluate this 4-year-old thread. It may not be what you want & you may have other/better ideas. I say that because the DSM node those guys talk about is not really visual / low-code programming. In fact, it's not even really functional programming. Anyhow, you can judge for yourself once you have a bit knowledge
PS. I will be closing this old thread.
first stop...
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.
JSON? Sting? Object?
This post should help to clarify the difference between Javascript objects and JSON.
When it is an object, it is REALLY EASY to grab parts of the msg...
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.
Forum stuff...
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
other resources...
- https://flows.nodered.org/ - nodes, readmes, demo flows
- https://cookbook.nodered.org/ - common patterns.
Good luck.
