Good morning, I'm new to node-red and how can I make it, for example, when clicking on a button, it loads the content of a text and displays it? Is there any training, tutorial or handout?
Welcome to the forum @rcalves
What do you mean by "loads the content of a text"?
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.
All what you need to use is a dashboard button, a file node and a text node, link them together and configure each one to send the msg payload to the next one.