How to properly install Node.js and npm to work?

Question

Node.js

I recently installed Node.js on my laptop, then during development I installed npm packages (basically, as described in the tutorials). Recently I discovered that the laptop was slowing down, rummaged around - and for some reason there were a bunch of files from my various projects in the shared folder. Deleted shorter to zero about 90,000 files.
Now I want to do everything right from the beginning so that Node.js is installed globally on the laptop (as I understand it, I can use it as a server on localhost and as a development environment for projects).
But on projects I want to install the necessary npm so that they work only for a specific project, without clogging the laptop. Ie, I made a project, posted a prod, deleted the folder and with it all the tinsel that was not needed.
It seems that he did everything according to the principle of global-local installation, but the laptop, nevertheless, became clogged. Mb, missed something.
How to organize everything correctly?

Answer 1

what does global and local mean? everything is installed via npm .