You post your question in wrong subforum.
But you need to learn javascript from scratch. For me... Best page for learning javascript is https://www.w3schools.com/js/default.asp
You have good amount of examples and simple codes... After you learn javascript syntax you can pass to node.js.
Node.js is for server side scripting. https://www.w3schools.com/nodejs/ or https://nodejs.org/api/all.html
You dont need to know every detail in node.js... Just simple events, how to add packages with npm install or how to send mail from nodejs.
When you learn all this... You will later need to use some database to store some variables and pull it back when you will need it again. I prefer. using mysql or mongoDB. Google it because there is more options for databases.